XML 120 R95.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Schedule III - Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | $ 164,506 |  |  |
Initial Cost |  |  |  |
Land | 697,810 |  |  |
Building and Land Improvements | 2,902,516 |  |  |
Costs Capitalized Subsequent to Acquisition | 380,487 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 697,810 |  |  |
Building and Land Improvements | 3,283,003 |  |  |
Total | 3,980,813 | $ 3,874,715 | $ 4,158,616 | $ 4,014,336
Accumulated Depreciation | (801,038) | (715,951) | (718,680) | $ (703,083)
Additional information |  |  |  |
Debt excluded from encumbrances | 1,828,333 | 1,904,001 |  |
Net discounts and deferred financing costs | 13,800 |  |  |
Aggregate cost of assets for federal income tax purposes | 3,500,000 |  |  |
Impairment losses | $ 15,123 | 101,391 | $ 23,289 |
Buildings improvements [Member] | Minimum [Member] |  |  |  |
Additional information |  |  |  |
Estimated lives over which depreciation is recognized | 10 years |  |  |
Buildings improvements [Member] | Maximum [Member] |  |  |  |
Additional information |  |  |  |
Estimated lives over which depreciation is recognized | 40 years |  |  |
Term Loan Facilities [Member] |  |  |  |
Additional information |  |  |  |
Debt excluded from encumbrances | $ 347,959 | $ 547,494 |  |
Unsecured Senior Notes [Member] |  |  |  |
Additional information |  |  |  |
Debt excluded from encumbrances | 1,200,000 |  |  |
Unsecured notes payable [Member] |  |  |  |
Additional information |  |  |  |
Debt excluded from encumbrances | 1,300 |  |  |
Fixed rate mortgage loans [Member] |  |  |  |
Additional information |  |  |  |
Net discounts and deferred financing costs | 668 |  |  |
100 Light Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 49,378 |  |  |
Initial Cost |  |  |  |
Land | 26,715 |  |  |
Building and Land Improvements | 58,343 |  |  |
Costs Capitalized Subsequent to Acquisition | 5,286 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 26,715 |  |  |
Building and Land Improvements | 63,629 |  |  |
Total | 90,344 |  |  |
Accumulated Depreciation | (9,467) |  |  |
1000 Redstone Gateway [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 10,730 |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 20,533 |  |  |
Costs Capitalized Subsequent to Acquisition | 5 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 20,538 |  |  |
Total | 20,538 |  |  |
Accumulated Depreciation | (2,465) |  |  |
1100 Redstone Gateway [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 11,222 |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 19,593 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 19,593 |  |  |
Total | 19,593 |  |  |
Accumulated Depreciation | (1,945) |  |  |
114 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 364 |  |  |
Building and Land Improvements | 3,109 |  |  |
Costs Capitalized Subsequent to Acquisition | 118 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 364 |  |  |
Building and Land Improvements | 3,227 |  |  |
Total | 3,591 |  |  |
Accumulated Depreciation | (1,309) |  |  |
11751 Meadowville Lane [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,305 |  |  |
Building and Land Improvements | 52,098 |  |  |
Costs Capitalized Subsequent to Acquisition | 112 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,305 |  |  |
Building and Land Improvements | 52,210 |  |  |
Total | 53,515 |  |  |
Accumulated Depreciation | (14,845) |  |  |
1200 Redstone Gateway [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 12,973 |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 22,389 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 22,389 |  |  |
Total | 22,389 |  |  |
Accumulated Depreciation | (2,264) |  |  |
1201 M Street [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 49,785 |  |  |
Costs Capitalized Subsequent to Acquisition | 8,590 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 58,375 |  |  |
Total | 58,375 |  |  |
Accumulated Depreciation | (12,800) |  |  |
1201 Winterson Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,288 |  |  |
Building and Land Improvements | 16,433 |  |  |
Costs Capitalized Subsequent to Acquisition | 460 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,288 |  |  |
Building and Land Improvements | 16,893 |  |  |
Total | 18,181 |  |  |
Accumulated Depreciation | (4,279) |  |  |
1220 12th Street, SE [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 42,464 |  |  |
Costs Capitalized Subsequent to Acquisition | 5,820 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 48,284 |  |  |
Total | 48,284 |  |  |
Accumulated Depreciation | (11,719) |  |  |
1243 Winterson Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 630 |  |  |
Building and Land Improvements | 0 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 630 |  |  |
Building and Land Improvements | 0 |  |  |
Total | 630 |  |  |
131 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,906 |  |  |
Building and Land Improvements | 7,623 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,868 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,906 |  |  |
Building and Land Improvements | 11,491 |  |  |
Total | 13,397 |  |  |
Accumulated Depreciation | (6,286) |  |  |
132 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,917 |  |  |
Building and Land Improvements | 12,259 |  |  |
Costs Capitalized Subsequent to Acquisition | 4,124 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,917 |  |  |
Building and Land Improvements | 16,383 |  |  |
Total | 19,300 |  |  |
Accumulated Depreciation | (8,715) |  |  |
133 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,517 |  |  |
Building and Land Improvements | 10,068 |  |  |
Costs Capitalized Subsequent to Acquisition | 5,544 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,517 |  |  |
Building and Land Improvements | 15,612 |  |  |
Total | 18,129 |  |  |
Accumulated Depreciation | (9,234) |  |  |
134 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,684 |  |  |
Building and Land Improvements | 7,517 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,691 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,684 |  |  |
Building and Land Improvements | 11,208 |  |  |
Total | 14,892 |  |  |
Accumulated Depreciation | (5,419) |  |  |
1340 Ashton Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 905 |  |  |
Building and Land Improvements | 3,620 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,470 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 905 |  |  |
Building and Land Improvements | 5,090 |  |  |
Total | 5,995 |  |  |
Accumulated Depreciation | (2,854) |  |  |
13450 Sunrise Valley Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,386 |  |  |
Building and Land Improvements | 5,576 |  |  |
Costs Capitalized Subsequent to Acquisition | 4,553 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,386 |  |  |
Building and Land Improvements | 10,129 |  |  |
Total | 11,515 |  |  |
Accumulated Depreciation | (4,808) |  |  |
13454 Sunrise Valley Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,899 |  |  |
Building and Land Improvements | 11,986 |  |  |
Costs Capitalized Subsequent to Acquisition | 7,071 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,899 |  |  |
Building and Land Improvements | 19,057 |  |  |
Total | 21,956 |  |  |
Accumulated Depreciation | (9,262) |  |  |
135 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,484 |  |  |
Building and Land Improvements | 9,750 |  |  |
Costs Capitalized Subsequent to Acquisition | 6,075 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,484 |  |  |
Building and Land Improvements | 15,825 |  |  |
Total | 18,309 |  |  |
Accumulated Depreciation | (7,970) |  |  |
1362 Mellon Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 950 |  |  |
Building and Land Improvements | 3,864 |  |  |
Costs Capitalized Subsequent to Acquisition | 206 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 950 |  |  |
Building and Land Improvements | 4,070 |  |  |
Total | 5,020 |  |  |
Accumulated Depreciation | (192) |  |  |
13857 McLearen Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,507 |  |  |
Building and Land Improvements | 30,177 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,768 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,507 |  |  |
Building and Land Improvements | 31,945 |  |  |
Total | 35,452 |  |  |
Accumulated Depreciation | (10,100) |  |  |
140 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,407 |  |  |
Building and Land Improvements | 24,167 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,487 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,407 |  |  |
Building and Land Improvements | 25,654 |  |  |
Total | 29,061 |  |  |
Accumulated Depreciation | (8,907) |  |  |
141 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,398 |  |  |
Building and Land Improvements | 9,538 |  |  |
Costs Capitalized Subsequent to Acquisition | 4,815 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,398 |  |  |
Building and Land Improvements | 14,353 |  |  |
Total | 16,751 |  |  |
Accumulated Depreciation | (7,409) |  |  |
14280 Park Meadow Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,731 |  |  |
Building and Land Improvements | 15,953 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,628 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,731 |  |  |
Building and Land Improvements | 18,581 |  |  |
Total | 22,312 |  |  |
Accumulated Depreciation | (7,326) |  |  |
1460 Dorsey Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,577 |  |  |
Building and Land Improvements | 33 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,577 |  |  |
Building and Land Improvements | 33 |  |  |
Total | 1,610 |  |  |
14840 Conference Center Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,572 |  |  |
Building and Land Improvements | 8,175 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,092 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,572 |  |  |
Building and Land Improvements | 11,267 |  |  |
Total | 12,839 |  |  |
Accumulated Depreciation | (5,410) |  |  |
14850 Conference Center Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,615 |  |  |
Building and Land Improvements | 8,358 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,072 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,615 |  |  |
Building and Land Improvements | 11,430 |  |  |
Total | 13,045 |  |  |
Accumulated Depreciation | (5,857) |  |  |
14900 Conference Center Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,436 |  |  |
Building and Land Improvements | 14,402 |  |  |
Costs Capitalized Subsequent to Acquisition | 6,239 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,436 |  |  |
Building and Land Improvements | 20,641 |  |  |
Total | 24,077 |  |  |
Accumulated Depreciation | (10,027) |  |  |
1501 South Clinton Street [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 27,964 |  |  |
Building and Land Improvements | 51,990 |  |  |
Costs Capitalized Subsequent to Acquisition | 13,670 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 27,964 |  |  |
Building and Land Improvements | 65,660 |  |  |
Total | 93,624 |  |  |
Accumulated Depreciation | (19,942) |  |  |
15049 Conference Center Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 4,415 |  |  |
Building and Land Improvements | 20,365 |  |  |
Costs Capitalized Subsequent to Acquisition | 14,994 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 4,415 |  |  |
Building and Land Improvements | 35,359 |  |  |
Total | 39,774 |  |  |
Accumulated Depreciation | (12,097) |  |  |
15059 Conference Center Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 5,753 |  |  |
Building and Land Improvements | 13,615 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,645 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 5,753 |  |  |
Building and Land Improvements | 17,260 |  |  |
Total | 23,013 |  |  |
Accumulated Depreciation | (7,907) |  |  |
1550 West Nursery Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 14,071 |  |  |
Building and Land Improvements | 16,930 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 14,071 |  |  |
Building and Land Improvements | 16,930 |  |  |
Total | 31,001 |  |  |
Accumulated Depreciation | (4,802) |  |  |
1560 West Nursery Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,441 |  |  |
Building and Land Improvements | 113 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,441 |  |  |
Building and Land Improvements | 113 |  |  |
Total | 1,554 |  |  |
Accumulated Depreciation | (10) |  |  |
1610 West Nursery Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 259 |  |  |
Building and Land Improvements | 246 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 259 |  |  |
Building and Land Improvements | 246 |  |  |
Total | 505 |  |  |
Accumulated Depreciation | (5) |  |  |
1616 West Nursery Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 393 |  |  |
Building and Land Improvements | 2,919 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 393 |  |  |
Building and Land Improvements | 2,919 |  |  |
Total | 3,312 |  |  |
Accumulated Depreciation | (13) |  |  |
1622 West Nursery Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 393 |  |  |
Building and Land Improvements | 2,477 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 393 |  |  |
Building and Land Improvements | 2,477 |  |  |
Total | 2,870 |  |  |
Accumulated Depreciation | (53) |  |  |
16442 Commerce Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 613 |  |  |
Building and Land Improvements | 2,582 |  |  |
Costs Capitalized Subsequent to Acquisition | 891 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 613 |  |  |
Building and Land Improvements | 3,473 |  |  |
Total | 4,086 |  |  |
Accumulated Depreciation | (1,538) |  |  |
16480 Commerce Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,856 |  |  |
Building and Land Improvements | 7,425 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,068 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,856 |  |  |
Building and Land Improvements | 9,493 |  |  |
Total | 11,349 |  |  |
Accumulated Depreciation | (3,279) |  |  |
16501 Commerce Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 522 |  |  |
Building and Land Improvements | 2,090 |  |  |
Costs Capitalized Subsequent to Acquisition | 727 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 522 |  |  |
Building and Land Improvements | 2,817 |  |  |
Total | 3,339 |  |  |
Accumulated Depreciation | (975) |  |  |
16539 Commerce Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 688 |  |  |
Building and Land Improvements | 2,860 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,892 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 688 |  |  |
Building and Land Improvements | 4,752 |  |  |
Total | 5,440 |  |  |
Accumulated Depreciation | (2,325) |  |  |
16541 Commerce Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 773 |  |  |
Building and Land Improvements | 3,094 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,757 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 773 |  |  |
Building and Land Improvements | 4,851 |  |  |
Total | 5,624 |  |  |
Accumulated Depreciation | (2,026) |  |  |
16543 Commerce Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 436 |  |  |
Building and Land Improvements | 1,742 |  |  |
Costs Capitalized Subsequent to Acquisition | 716 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 436 |  |  |
Building and Land Improvements | 2,458 |  |  |
Total | 2,894 |  |  |
Accumulated Depreciation | (839) |  |  |
1751 Pinnacle Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 10,486 |  |  |
Building and Land Improvements | 42,339 |  |  |
Costs Capitalized Subsequent to Acquisition | 27,048 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 10,486 |  |  |
Building and Land Improvements | 69,387 |  |  |
Total | 79,873 |  |  |
Accumulated Depreciation | (29,582) |  |  |
1753 Pinnacle Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 8,275 |  |  |
Building and Land Improvements | 34,353 |  |  |
Costs Capitalized Subsequent to Acquisition | 16,648 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 8,275 |  |  |
Building and Land Improvements | 51,001 |  |  |
Total | 59,276 |  |  |
Accumulated Depreciation | (18,757) |  |  |
206 Research Boulevard [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 132 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 132 |  |  |
Total | 132 |  |  |
Accumulated Depreciation | (132) |  |  |
209 Research Boulevard [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 134 |  |  |
Building and Land Improvements | 1,711 |  |  |
Costs Capitalized Subsequent to Acquisition | 175 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 134 |  |  |
Building and Land Improvements | 1,886 |  |  |
Total | 2,020 |  |  |
Accumulated Depreciation | (283) |  |  |
210 Research Boulevard [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 113 |  |  |
Building and Land Improvements | 1,402 |  |  |
Costs Capitalized Subsequent to Acquisition | 86 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 113 |  |  |
Building and Land Improvements | 1,488 |  |  |
Total | 1,601 |  |  |
Accumulated Depreciation | (174) |  |  |
2100 L Street [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 55,615 |  |  |
Building and Land Improvements | 9,073 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 55,615 |  |  |
Building and Land Improvements | 9,073 |  |  |
Total | 64,688 |  |  |
2100 Rideout Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 5,003 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,881 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 7,884 |  |  |
Total | 7,884 |  |  |
Accumulated Depreciation | (438) |  |  |
22289 Exploration Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,422 |  |  |
Building and Land Improvements | 5,719 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,829 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,422 |  |  |
Building and Land Improvements | 7,548 |  |  |
Total | 8,970 |  |  |
Accumulated Depreciation | (3,415) |  |  |
22299 Exploration Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,362 |  |  |
Building and Land Improvements | 5,791 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,308 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,362 |  |  |
Building and Land Improvements | 8,099 |  |  |
Total | 9,461 |  |  |
Accumulated Depreciation | (3,768) |  |  |
22300 Exploration Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,094 |  |  |
Building and Land Improvements | 5,038 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,489 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,094 |  |  |
Building and Land Improvements | 6,527 |  |  |
Total | 7,621 |  |  |
Accumulated Depreciation | (2,432) |  |  |
22309 Exploration Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,243 |  |  |
Building and Land Improvements | 10,419 |  |  |
Costs Capitalized Subsequent to Acquisition | 7,967 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,243 |  |  |
Building and Land Improvements | 18,386 |  |  |
Total | 20,629 |  |  |
Accumulated Depreciation | (6,087) |  |  |
23535 Cottonwood Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 692 |  |  |
Building and Land Improvements | 3,051 |  |  |
Costs Capitalized Subsequent to Acquisition | 537 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 692 |  |  |
Building and Land Improvements | 3,588 |  |  |
Total | 4,280 |  |  |
Accumulated Depreciation | (1,527) |  |  |
250 W Pratt St [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 8,057 |  |  |
Building and Land Improvements | 34,588 |  |  |
Costs Capitalized Subsequent to Acquisition | 6,942 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 8,057 |  |  |
Building and Land Improvements | 41,530 |  |  |
Total | 49,587 |  |  |
Accumulated Depreciation | (6,972) |  |  |
2500 Riva Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,791 |  |  |
Building and Land Improvements | 12,145 |  |  |
Costs Capitalized Subsequent to Acquisition | 1 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,791 |  |  |
Building and Land Improvements | 12,146 |  |  |
Total | 14,937 |  |  |
Accumulated Depreciation | (5,105) |  |  |
2600 Park Tower Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 20,304 |  |  |
Building and Land Improvements | 34,443 |  |  |
Costs Capitalized Subsequent to Acquisition | 517 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 20,304 |  |  |
Building and Land Improvements | 34,960 |  |  |
Total | 55,264 |  |  |
Accumulated Depreciation | (3,708) |  |  |
2691 Technology Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,098 |  |  |
Building and Land Improvements | 17,334 |  |  |
Costs Capitalized Subsequent to Acquisition | 5,563 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,098 |  |  |
Building and Land Improvements | 22,897 |  |  |
Total | 24,995 |  |  |
Accumulated Depreciation | (9,630) |  |  |
2701 Technology Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,737 |  |  |
Building and Land Improvements | 15,266 |  |  |
Costs Capitalized Subsequent to Acquisition | 4,398 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,737 |  |  |
Building and Land Improvements | 19,664 |  |  |
Total | 21,401 |  |  |
Accumulated Depreciation | (9,676) |  |  |
2711 Technology Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,251 |  |  |
Building and Land Improvements | 21,611 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,899 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,251 |  |  |
Building and Land Improvements | 23,510 |  |  |
Total | 25,761 |  |  |
Accumulated Depreciation | (11,727) |  |  |
2720 Technology Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,863 |  |  |
Building and Land Improvements | 29,272 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,218 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,863 |  |  |
Building and Land Improvements | 30,490 |  |  |
Total | 34,353 |  |  |
Accumulated Depreciation | (10,261) |  |  |
2721 Technology Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 4,611 |  |  |
Building and Land Improvements | 14,597 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,270 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 4,611 |  |  |
Building and Land Improvements | 15,867 |  |  |
Total | 20,478 |  |  |
Accumulated Depreciation | (7,484) |  |  |
2730 Hercules Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 8,737 |  |  |
Building and Land Improvements | 31,612 |  |  |
Costs Capitalized Subsequent to Acquisition | 8,697 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 8,737 |  |  |
Building and Land Improvements | 40,309 |  |  |
Total | 49,046 |  |  |
Accumulated Depreciation | (18,673) |  |  |
30 Light Street [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 4,153 |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 12,101 |  |  |
Costs Capitalized Subsequent to Acquisition | 629 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 12,730 |  |  |
Total | 12,730 |  |  |
Accumulated Depreciation | (753) |  |  |
300 Sentinel Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,517 |  |  |
Building and Land Improvements | 59,165 |  |  |
Costs Capitalized Subsequent to Acquisition | 925 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,517 |  |  |
Building and Land Improvements | 60,090 |  |  |
Total | 61,607 |  |  |
Accumulated Depreciation | (11,562) |  |  |
302 Sentinel Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,648 |  |  |
Building and Land Improvements | 29,687 |  |  |
Costs Capitalized Subsequent to Acquisition | 468 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,648 |  |  |
Building and Land Improvements | 30,155 |  |  |
Total | 32,803 |  |  |
Accumulated Depreciation | (7,579) |  |  |
304 Sentinel Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,411 |  |  |
Building and Land Improvements | 24,917 |  |  |
Costs Capitalized Subsequent to Acquisition | 202 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,411 |  |  |
Building and Land Improvements | 25,119 |  |  |
Total | 28,530 |  |  |
Accumulated Depreciation | (7,610) |  |  |
306 Sentinel Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,260 |  |  |
Building and Land Improvements | 22,592 |  |  |
Costs Capitalized Subsequent to Acquisition | 961 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,260 |  |  |
Building and Land Improvements | 23,553 |  |  |
Total | 26,813 |  |  |
Accumulated Depreciation | (6,631) |  |  |
308 Sentinel Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,422 |  |  |
Building and Land Improvements | 26,208 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,396 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,422 |  |  |
Building and Land Improvements | 28,604 |  |  |
Total | 30,026 |  |  |
Accumulated Depreciation | (4,370) |  |  |
310 Sentinel Way [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,372 |  |  |
Building and Land Improvements | 38,865 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,372 |  |  |
Building and Land Improvements | 38,865 |  |  |
Total | 41,237 |  |  |
Accumulated Depreciation | (1,977) |  |  |
310 The Bridge Street [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 261 |  |  |
Building and Land Improvements | 26,531 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,762 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 261 |  |  |
Building and Land Improvements | 30,293 |  |  |
Total | 30,554 |  |  |
Accumulated Depreciation | (7,430) |  |  |
312 Sentinel Way [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,138 |  |  |
Building and Land Improvements | 27,797 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,138 |  |  |
Building and Land Improvements | 27,797 |  |  |
Total | 30,935 |  |  |
Accumulated Depreciation | (2,304) |  |  |
314 Sentinel Way [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,254 |  |  |
Building and Land Improvements | 7,741 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,254 |  |  |
Building and Land Improvements | 7,741 |  |  |
Total | 8,995 |  |  |
Accumulated Depreciation | (548) |  |  |
316 Sentinel Way [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,748 |  |  |
Building and Land Improvements | 38,156 |  |  |
Costs Capitalized Subsequent to Acquisition | 145 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,748 |  |  |
Building and Land Improvements | 38,301 |  |  |
Total | 41,049 |  |  |
Accumulated Depreciation | (5,507) |  |  |
318 Sentinel Way [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,185 |  |  |
Building and Land Improvements | 28,426 |  |  |
Costs Capitalized Subsequent to Acquisition | 560 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,185 |  |  |
Building and Land Improvements | 28,986 |  |  |
Total | 31,171 |  |  |
Accumulated Depreciation | (8,416) |  |  |
320 Sentinel Way [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,067 |  |  |
Building and Land Improvements | 21,623 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,067 |  |  |
Building and Land Improvements | 21,623 |  |  |
Total | 23,690 |  |  |
Accumulated Depreciation | (5,391) |  |  |
322 Sentinel Way [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,605 |  |  |
Building and Land Improvements | 22,827 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,900 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,605 |  |  |
Building and Land Improvements | 24,727 |  |  |
Total | 27,332 |  |  |
Accumulated Depreciation | (6,286) |  |  |
324 Sentinel Way [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,656 |  |  |
Building and Land Improvements | 23,018 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,656 |  |  |
Building and Land Improvements | 23,018 |  |  |
Total | 24,674 |  |  |
Accumulated Depreciation | (4,229) |  |  |
4000 Market Street [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 466 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 466 |  |  |
Total | 466 |  |  |
4100 Market Street [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 1,013 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 1,013 |  |  |
Total | 1,013 |  |  |
410 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,831 |  |  |
Building and Land Improvements | 23,257 |  |  |
Costs Capitalized Subsequent to Acquisition | 119 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,831 |  |  |
Building and Land Improvements | 23,376 |  |  |
Total | 25,207 |  |  |
Accumulated Depreciation | (2,904) |  |  |
420 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,370 |  |  |
Building and Land Improvements | 27,750 |  |  |
Costs Capitalized Subsequent to Acquisition | 108 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,370 |  |  |
Building and Land Improvements | 27,858 |  |  |
Total | 30,228 |  |  |
Accumulated Depreciation | (2,635) |  |  |
430 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,852 |  |  |
Building and Land Improvements | 21,563 |  |  |
Costs Capitalized Subsequent to Acquisition | 126 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,852 |  |  |
Building and Land Improvements | 21,689 |  |  |
Total | 23,541 |  |  |
Accumulated Depreciation | (3,127) |  |  |
44408 Pecan Court [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 817 |  |  |
Building and Land Improvements | 1,583 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,490 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 817 |  |  |
Building and Land Improvements | 3,073 |  |  |
Total | 3,890 |  |  |
Accumulated Depreciation | (838) |  |  |
44414 Pecan Court [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 405 |  |  |
Building and Land Improvements | 1,619 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,033 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 405 |  |  |
Building and Land Improvements | 2,652 |  |  |
Total | 3,057 |  |  |
Accumulated Depreciation | (954) |  |  |
44417 Pecan Court [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 434 |  |  |
Building and Land Improvements | 3,822 |  |  |
Costs Capitalized Subsequent to Acquisition | 148 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 434 |  |  |
Building and Land Improvements | 3,970 |  |  |
Total | 4,404 |  |  |
Accumulated Depreciation | (1,448) |  |  |
44420 Pecan Court [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 344 |  |  |
Building and Land Improvements | 890 |  |  |
Costs Capitalized Subsequent to Acquisition | 168 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 344 |  |  |
Building and Land Improvements | 1,058 |  |  |
Total | 1,402 |  |  |
Accumulated Depreciation | (368) |  |  |
44425 Pecan Court [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,309 |  |  |
Building and Land Improvements | 3,506 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,881 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,309 |  |  |
Building and Land Improvements | 5,387 |  |  |
Total | 6,696 |  |  |
Accumulated Depreciation | (2,419) |  |  |
45310 Abell House Lane [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,272 |  |  |
Building and Land Improvements | 13,808 |  |  |
Costs Capitalized Subsequent to Acquisition | 147 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,272 |  |  |
Building and Land Improvements | 13,955 |  |  |
Total | 16,227 |  |  |
Accumulated Depreciation | (2,094) |  |  |
46579 Expedition Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,406 |  |  |
Building and Land Improvements | 5,796 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,680 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,406 |  |  |
Building and Land Improvements | 7,476 |  |  |
Total | 8,882 |  |  |
Accumulated Depreciation | (3,421) |  |  |
46591 Expedition Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,200 |  |  |
Building and Land Improvements | 7,199 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,226 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,200 |  |  |
Building and Land Improvements | 8,425 |  |  |
Total | 9,625 |  |  |
Accumulated Depreciation | (2,652) |  |  |
4851 Stonecroft Boulevard [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,878 |  |  |
Building and Land Improvements | 11,558 |  |  |
Costs Capitalized Subsequent to Acquisition | 21 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,878 |  |  |
Building and Land Improvements | 11,579 |  |  |
Total | 13,457 |  |  |
Accumulated Depreciation | (3,827) |  |  |
540 National Business Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,035 |  |  |
Building and Land Improvements | 29,490 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,035 |  |  |
Building and Land Improvements | 29,490 |  |  |
Total | 31,525 |  |  |
Accumulated Depreciation | (260) |  |  |
5520 Research Park Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 20,072 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,018 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 21,090 |  |  |
Total | 21,090 |  |  |
Accumulated Depreciation | (4,260) |  |  |
5522 Research Park Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 4,550 |  |  |
Costs Capitalized Subsequent to Acquisition | 210 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 4,760 |  |  |
Total | 4,760 |  |  |
Accumulated Depreciation | (1,185) |  |  |
5801 University Research Court [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 9,423 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 9,423 |  |  |
Total | 9,423 |  |  |
Accumulated Depreciation | (36) |  |  |
5825 University Research Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 21,284 |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 22,771 |  |  |
Costs Capitalized Subsequent to Acquisition | 666 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 23,437 |  |  |
Total | 23,437 |  |  |
Accumulated Depreciation | (5,020) |  |  |
5850 University Research Court [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 22,517 |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 31,906 |  |  |
Costs Capitalized Subsequent to Acquisition | 405 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 32,311 |  |  |
Total | 32,311 |  |  |
Accumulated Depreciation | (6,306) |  |  |
6700 Alexander Bell Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,755 |  |  |
Building and Land Improvements | 7,019 |  |  |
Costs Capitalized Subsequent to Acquisition | 6,866 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,755 |  |  |
Building and Land Improvements | 13,885 |  |  |
Total | 15,640 |  |  |
Accumulated Depreciation | (6,916) |  |  |
6708 Alexander Bell Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 897 |  |  |
Building and Land Improvements | 11,984 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,605 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 897 |  |  |
Building and Land Improvements | 13,589 |  |  |
Total | 14,486 |  |  |
Accumulated Depreciation | (3,839) |  |  |
6711 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,683 |  |  |
Building and Land Improvements | 23,239 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,278 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,683 |  |  |
Building and Land Improvements | 24,517 |  |  |
Total | 27,200 |  |  |
Accumulated Depreciation | (6,817) |  |  |
6716 Alexander Bell Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,242 |  |  |
Building and Land Improvements | 4,969 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,754 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,242 |  |  |
Building and Land Improvements | 8,723 |  |  |
Total | 9,965 |  |  |
Accumulated Depreciation | (5,129) |  |  |
6721 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,753 |  |  |
Building and Land Improvements | 34,090 |  |  |
Costs Capitalized Subsequent to Acquisition | 102 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,753 |  |  |
Building and Land Improvements | 34,192 |  |  |
Total | 35,945 |  |  |
Accumulated Depreciation | (7,514) |  |  |
6724 Alexander Bell Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 449 |  |  |
Building and Land Improvements | 5,039 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,374 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 449 |  |  |
Building and Land Improvements | 6,413 |  |  |
Total | 6,862 |  |  |
Accumulated Depreciation | (2,670) |  |  |
6731 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,807 |  |  |
Building and Land Improvements | 19,098 |  |  |
Costs Capitalized Subsequent to Acquisition | 4,872 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,807 |  |  |
Building and Land Improvements | 23,970 |  |  |
Total | 26,777 |  |  |
Accumulated Depreciation | (10,176) |  |  |
6740 Alexander Bell Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,424 |  |  |
Building and Land Improvements | 5,696 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,321 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,424 |  |  |
Building and Land Improvements | 9,017 |  |  |
Total | 10,441 |  |  |
Accumulated Depreciation | (5,698) |  |  |
6741 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 675 |  |  |
Building and Land Improvements | 1,711 |  |  |
Costs Capitalized Subsequent to Acquisition | 124 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 675 |  |  |
Building and Land Improvements | 1,835 |  |  |
Total | 2,510 |  |  |
Accumulated Depreciation | (466) |  |  |
6750 Alexander Bell Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,263 |  |  |
Building and Land Improvements | 12,461 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,959 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,263 |  |  |
Building and Land Improvements | 16,420 |  |  |
Total | 17,683 |  |  |
Accumulated Depreciation | (8,761) |  |  |
6760 Alexander Bell Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 890 |  |  |
Building and Land Improvements | 3,561 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,358 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 890 |  |  |
Building and Land Improvements | 6,919 |  |  |
Total | 7,809 |  |  |
Accumulated Depreciation | (3,932) |  |  |
6940 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,545 |  |  |
Building and Land Improvements | 9,916 |  |  |
Costs Capitalized Subsequent to Acquisition | 7,095 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,545 |  |  |
Building and Land Improvements | 17,011 |  |  |
Total | 20,556 |  |  |
Accumulated Depreciation | (8,164) |  |  |
6950 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,596 |  |  |
Building and Land Improvements | 14,269 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,238 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,596 |  |  |
Building and Land Improvements | 17,507 |  |  |
Total | 21,103 |  |  |
Accumulated Depreciation | (8,787) |  |  |
7000 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,131 |  |  |
Building and Land Improvements | 12,103 |  |  |
Costs Capitalized Subsequent to Acquisition | 5,085 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,131 |  |  |
Building and Land Improvements | 17,188 |  |  |
Total | 20,319 |  |  |
Accumulated Depreciation | (6,178) |  |  |
7005 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,036 |  |  |
Building and Land Improvements | 753 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,036 |  |  |
Building and Land Improvements | 753 |  |  |
Total | 3,789 |  |  |
7015 Albert Einstein Drive [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 829 |  |  |
Initial Cost |  |  |  |
Land | 2,058 |  |  |
Building and Land Improvements | 6,093 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,178 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,058 |  |  |
Building and Land Improvements | 8,271 |  |  |
Total | 10,329 |  |  |
Accumulated Depreciation | (3,343) |  |  |
7061 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 729 |  |  |
Building and Land Improvements | 3,094 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,018 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 729 |  |  |
Building and Land Improvements | 5,112 |  |  |
Total | 5,841 |  |  |
Accumulated Depreciation | (2,191) |  |  |
7063 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 902 |  |  |
Building and Land Improvements | 3,684 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,151 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 902 |  |  |
Building and Land Improvements | 6,835 |  |  |
Total | 7,737 |  |  |
Accumulated Depreciation | (3,113) |  |  |
7065 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 919 |  |  |
Building and Land Improvements | 3,763 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,095 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 919 |  |  |
Building and Land Improvements | 6,858 |  |  |
Total | 7,777 |  |  |
Accumulated Depreciation | (3,637) |  |  |
7067 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,829 |  |  |
Building and Land Improvements | 11,823 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,051 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,829 |  |  |
Building and Land Improvements | 14,874 |  |  |
Total | 16,703 |  |  |
Accumulated Depreciation | (7,037) |  |  |
7125 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,361 |  |  |
Building and Land Improvements | 2,354 |  |  |
Costs Capitalized Subsequent to Acquisition | 279 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,361 |  |  |
Building and Land Improvements | 2,633 |  |  |
Total | 5,994 |  |  |
7125 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 17,126 |  |  |
Building and Land Improvements | 46,994 |  |  |
Costs Capitalized Subsequent to Acquisition | 15,786 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 17,126 |  |  |
Building and Land Improvements | 62,780 |  |  |
Total | 79,906 |  |  |
Accumulated Depreciation | (20,876) |  |  |
7130 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,350 |  |  |
Building and Land Improvements | 4,359 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,534 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,350 |  |  |
Building and Land Improvements | 6,893 |  |  |
Total | 8,243 |  |  |
Accumulated Depreciation | (3,192) |  |  |
7134 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 704 |  |  |
Building and Land Improvements | 4,707 |  |  |
Costs Capitalized Subsequent to Acquisition | 353 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 704 |  |  |
Building and Land Improvements | 5,060 |  |  |
Total | 5,764 |  |  |
Accumulated Depreciation | (1,422) |  |  |
7138 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,104 |  |  |
Building and Land Improvements | 3,518 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,729 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,104 |  |  |
Building and Land Improvements | 6,247 |  |  |
Total | 7,351 |  |  |
Accumulated Depreciation | (3,459) |  |  |
7142 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,342 |  |  |
Building and Land Improvements | 4,657 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,608 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,342 |  |  |
Building and Land Improvements | 7,265 |  |  |
Total | 8,607 |  |  |
Accumulated Depreciation | (2,796) |  |  |
7150 Columbia Gateway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,032 |  |  |
Building and Land Improvements | 3,429 |  |  |
Costs Capitalized Subsequent to Acquisition | 813 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,032 |  |  |
Building and Land Improvements | 4,242 |  |  |
Total | 5,274 |  |  |
Accumulated Depreciation | (1,439) |  |  |
7150 Riverwood Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,821 |  |  |
Building and Land Improvements | 4,388 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,774 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,821 |  |  |
Building and Land Improvements | 6,162 |  |  |
Total | 7,983 |  |  |
Accumulated Depreciation | (2,343) |  |  |
7160 Riverwood Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,732 |  |  |
Building and Land Improvements | 7,006 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,455 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,732 |  |  |
Building and Land Improvements | 9,461 |  |  |
Total | 12,193 |  |  |
Accumulated Depreciation | (3,778) |  |  |
7170 Riverwood Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,283 |  |  |
Building and Land Improvements | 3,096 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,465 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,283 |  |  |
Building and Land Improvements | 4,561 |  |  |
Total | 5,844 |  |  |
Accumulated Depreciation | (1,798) |  |  |
7175 Riverwood Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,788 |  |  |
Building and Land Improvements | 7,269 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,788 |  |  |
Building and Land Improvements | 7,269 |  |  |
Total | 9,057 |  |  |
Accumulated Depreciation | (752) |  |  |
7200 Redstone Gateway [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 6,303 |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 8,348 |  |  |
Costs Capitalized Subsequent to Acquisition | 5 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 8,353 |  |  |
Total | 8,353 |  |  |
Accumulated Depreciation | (752) |  |  |
7200 Riverwood Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 4,089 |  |  |
Building and Land Improvements | 22,630 |  |  |
Costs Capitalized Subsequent to Acquisition | 4,532 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 4,089 |  |  |
Building and Land Improvements | 27,162 |  |  |
Total | 31,251 |  |  |
Accumulated Depreciation | (10,180) |  |  |
7205 Riverwood Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,367 |  |  |
Building and Land Improvements | 21,419 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,367 |  |  |
Building and Land Improvements | 21,419 |  |  |
Total | 22,786 |  |  |
Accumulated Depreciation | (2,381) |  |  |
7272 Park Circle Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,479 |  |  |
Building and Land Improvements | 6,300 |  |  |
Costs Capitalized Subsequent to Acquisition | 4,578 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,479 |  |  |
Building and Land Improvements | 10,878 |  |  |
Total | 12,357 |  |  |
Accumulated Depreciation | (3,898) |  |  |
7318 Parkway Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 972 |  |  |
Building and Land Improvements | 3,888 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,239 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 972 |  |  |
Building and Land Improvements | 5,127 |  |  |
Total | 6,099 |  |  |
Accumulated Depreciation | (2,398) |  |  |
7400 Redstone Gateway [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 6,914 |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 9,223 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 9,223 |  |  |
Total | 9,223 |  |  |
Accumulated Depreciation | (582) |  |  |
7467 Ridge Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,565 |  |  |
Building and Land Improvements | 3,116 |  |  |
Costs Capitalized Subsequent to Acquisition | 4,264 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,565 |  |  |
Building and Land Improvements | 7,380 |  |  |
Total | 8,945 |  |  |
Accumulated Depreciation | (1,930) |  |  |
7740 Milestone Parkway [Member] |  |  |  |
Real Estate and Accumulated Depreciation |  |  |  |
Encumbrances | 18,203 |  |  |
Initial Cost |  |  |  |
Land | 3,825 |  |  |
Building and Land Improvements | 34,176 |  |  |
Costs Capitalized Subsequent to Acquisition | 567 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,825 |  |  |
Building and Land Improvements | 34,743 |  |  |
Total | 38,568 |  |  |
Accumulated Depreciation | (6,482) |  |  |
7770 Backlick Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 6,387 |  |  |
Building and Land Improvements | 76,315 |  |  |
Costs Capitalized Subsequent to Acquisition | 142 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 6,387 |  |  |
Building and Land Improvements | 76,457 |  |  |
Total | 82,844 |  |  |
Accumulated Depreciation | (9,075) |  |  |
7880 Milestone Parkway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 4,857 |  |  |
Building and Land Improvements | 24,677 |  |  |
Costs Capitalized Subsequent to Acquisition | 62 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 4,857 |  |  |
Building and Land Improvements | 24,739 |  |  |
Total | 29,596 |  |  |
Accumulated Depreciation | (1,382) |  |  |
8621 Robert Fulton Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,317 |  |  |
Building and Land Improvements | 12,642 |  |  |
Costs Capitalized Subsequent to Acquisition | 537 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,317 |  |  |
Building and Land Improvements | 13,179 |  |  |
Total | 15,496 |  |  |
Accumulated Depreciation | (4,097) |  |  |
8661 Robert Fulton Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,510 |  |  |
Building and Land Improvements | 3,764 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,453 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,510 |  |  |
Building and Land Improvements | 6,217 |  |  |
Total | 7,727 |  |  |
Accumulated Depreciation | (2,655) |  |  |
8671 Robert Fulton Drive [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,718 |  |  |
Building and Land Improvements | 4,280 |  |  |
Costs Capitalized Subsequent to Acquisition | 4,052 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,718 |  |  |
Building and Land Improvements | 8,332 |  |  |
Total | 10,050 |  |  |
Accumulated Depreciation | (3,688) |  |  |
870 Elkridge Landing Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,003 |  |  |
Building and Land Improvements | 9,442 |  |  |
Costs Capitalized Subsequent to Acquisition | 8,735 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,003 |  |  |
Building and Land Improvements | 18,177 |  |  |
Total | 20,180 |  |  |
Accumulated Depreciation | (9,370) |  |  |
891 Elkridge Landing Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,165 |  |  |
Building and Land Improvements | 4,772 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,466 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,165 |  |  |
Building and Land Improvements | 8,238 |  |  |
Total | 9,403 |  |  |
Accumulated Depreciation | (4,186) |  |  |
901 Elkridge Landing Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,156 |  |  |
Building and Land Improvements | 4,437 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,704 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,156 |  |  |
Building and Land Improvements | 7,141 |  |  |
Total | 8,297 |  |  |
Accumulated Depreciation | (3,608) |  |  |
911 Elkridge Landing Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,215 |  |  |
Building and Land Improvements | 4,861 |  |  |
Costs Capitalized Subsequent to Acquisition | 2,191 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,215 |  |  |
Building and Land Improvements | 7,052 |  |  |
Total | 8,267 |  |  |
Accumulated Depreciation | (3,899) |  |  |
938 Elkridge Landing Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 922 |  |  |
Building and Land Improvements | 4,748 |  |  |
Costs Capitalized Subsequent to Acquisition | 1,446 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 922 |  |  |
Building and Land Improvements | 6,194 |  |  |
Total | 7,116 |  |  |
Accumulated Depreciation | (2,621) |  |  |
939 Elkridge Landing Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 939 |  |  |
Building and Land Improvements | 3,756 |  |  |
Costs Capitalized Subsequent to Acquisition | 4,438 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 939 |  |  |
Building and Land Improvements | 8,194 |  |  |
Total | 9,133 |  |  |
Accumulated Depreciation | (4,254) |  |  |
940 Elkridge Landing Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 842 |  |  |
Building and Land Improvements | 4 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 842 |  |  |
Building and Land Improvements | 4 |  |  |
Total | 846 |  |  |
9651 Hornbaker Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 6,050 |  |  |
Building and Land Improvements | 249,142 |  |  |
Costs Capitalized Subsequent to Acquisition | 3,868 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 6,050 |  |  |
Building and Land Improvements | 253,010 |  |  |
Total | 259,060 |  |  |
Accumulated Depreciation | (39,294) |  |  |
Arundel Preserve [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 13,401 |  |  |
Building and Land Improvements | 9,578 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 13,401 |  |  |
Building and Land Improvements | 9,578 |  |  |
Total | 22,979 |  |  |
Bethlehem Tech Park-DC18 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,599 |  |  |
Building and Land Improvements | 25,992 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,599 |  |  |
Building and Land Improvements | 25,992 |  |  |
Total | 29,591 |  |  |
Accumulated Depreciation | (306) |  |  |
Bethlehem Tech Park-DC19 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,708 |  |  |
Building and Land Improvements | 16,362 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,708 |  |  |
Building and Land Improvements | 16,362 |  |  |
Total | 20,070 |  |  |
Accumulated Depreciation | (455) |  |  |
Bethlehem Tech Park-DC20 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 3,599 |  |  |
Building and Land Improvements | 23,625 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 3,599 |  |  |
Building and Land Improvements | 23,625 |  |  |
Total | 27,224 |  |  |
Accumulated Depreciation | (370) |  |  |
Bethlehem Tech Park - DC 23 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 479 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 479 |  |  |
Total | 479 |  |  |
BLC 1 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 12,035 |  |  |
Building and Land Improvements | 368 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 12,035 |  |  |
Building and Land Improvements | 368 |  |  |
Total | 12,403 |  |  |
BLC 2 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 12,035 |  |  |
Building and Land Improvements | 292 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 12,035 |  |  |
Building and Land Improvements | 292 |  |  |
Total | 12,327 |  |  |
Canton Crossing Land [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 16,085 |  |  |
Building and Land Improvements | 2,698 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 16,085 |  |  |
Building and Land Improvements | 2,698 |  |  |
Total | 18,783 |  |  |
Canton Crossing Util Distr Ctr [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 7,300 |  |  |
Building and Land Improvements | 15,556 |  |  |
Costs Capitalized Subsequent to Acquisition | 986 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 7,300 |  |  |
Building and Land Improvements | 16,542 |  |  |
Total | 23,842 |  |  |
Accumulated Depreciation | (4,475) |  |  |
Columbia Gateway - Southridge [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 6,387 |  |  |
Building and Land Improvements | 3,719 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 6,387 |  |  |
Building and Land Improvements | 3,719 |  |  |
Total | 10,106 |  |  |
Dahlgren Technology Center [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 978 |  |  |
Building and Land Improvements | 178 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 978 |  |  |
Building and Land Improvements | 178 |  |  |
Total | 1,156 |  |  |
Expedition VII [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 705 |  |  |
Building and Land Improvements | 729 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 705 |  |  |
Building and Land Improvements | 729 |  |  |
Total | 1,434 |  |  |
Innovation Park [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 4,443 |  |  |
Building and Land Improvements | 120 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 4,443 |  |  |
Building and Land Improvements | 120 |  |  |
Total | 4,563 |  |  |
M Square Research Park [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 3,571 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 3,571 |  |  |
Total | 3,571 |  |  |
MR Land [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 18,827 |  |  |
Building and Land Improvements | 293 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 18,827 |  |  |
Building and Land Improvements | 293 |  |  |
Total | 19,120 |  |  |
National Business Park North [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 28,066 |  |  |
Building and Land Improvements | 47,802 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 28,066 |  |  |
Building and Land Improvements | 47,802 |  |  |
Total | 75,868 |  |  |
North Gate Business Park [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,755 |  |  |
Building and Land Improvements | 0 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,755 |  |  |
Building and Land Improvements | 0 |  |  |
Total | 1,755 |  |  |
Northwest Crossroads [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 7,430 |  |  |
Building and Land Improvements | 847 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 7,430 |  |  |
Building and Land Improvements | 847 |  |  |
Total | 8,277 |  |  |
NOVA Office A [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 2,096 |  |  |
Building and Land Improvements | 46,835 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 2,096 |  |  |
Building and Land Improvements | 46,835 |  |  |
Total | 48,931 |  |  |
Accumulated Depreciation | (3,403) |  |  |
NOVA Office B [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 739 |  |  |
Building and Land Improvements | 27,128 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 739 |  |  |
Building and Land Improvements | 27,128 |  |  |
Total | 27,867 |  |  |
Accumulated Depreciation | (1,128) |  |  |
NOVA Office D [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 6,587 |  |  |
Building and Land Improvements | 38,758 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 6,587 |  |  |
Building and Land Improvements | 38,758 |  |  |
Total | 45,345 |  |  |
Accumulated Depreciation | (437) |  |  |
Old Annapolis Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,637 |  |  |
Building and Land Improvements | 5,500 |  |  |
Costs Capitalized Subsequent to Acquisition | 5,241 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,637 |  |  |
Building and Land Improvements | 10,741 |  |  |
Total | 12,378 |  |  |
Accumulated Depreciation | (3,509) |  |  |
Paragon Park - DC 21 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 7,828 |  |  |
Building and Land Improvements | 17,992 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 7,828 |  |  |
Building and Land Improvements | 17,992 |  |  |
Total | 25,820 |  |  |
Accumulated Depreciation | (100) |  |  |
Paragon Park - DC 22 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 7,828 |  |  |
Building and Land Improvements | 17,445 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 7,828 |  |  |
Building and Land Improvements | 17,445 |  |  |
Total | 25,273 |  |  |
Accumulated Depreciation | (68) |  |  |
Patriot Point - DC15 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 12,156 |  |  |
Building and Land Improvements | 17,069 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 12,156 |  |  |
Building and Land Improvements | 17,069 |  |  |
Total | 29,225 |  |  |
Accumulated Depreciation | (752) |  |  |
Patriot Point - DC16 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 12,156 |  |  |
Building and Land Improvements | 16,973 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 12,156 |  |  |
Building and Land Improvements | 16,973 |  |  |
Total | 29,129 |  |  |
Accumulated Depreciation | (709) |  |  |
Patriot Point - DC17 [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 6,078 |  |  |
Building and Land Improvements | 16,347 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 6,078 |  |  |
Building and Land Improvements | 16,347 |  |  |
Total | 22,425 |  |  |
Accumulated Depreciation | (520) |  |  |
Patriot Ridge [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 18,517 |  |  |
Building and Land Improvements | 14,467 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 18,517 |  |  |
Building and Land Improvements | 14,467 |  |  |
Total | 32,984 |  |  |
Redstone Gateway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 19,152 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 19,152 |  |  |
Total | 19,152 |  |  |
Route 15/Biggs Ford Road [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,129 |  |  |
Building and Land Improvements | 0 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,129 |  |  |
Building and Land Improvements | 0 |  |  |
Total | 1,129 |  |  |
Sentry Gateway [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 8,275 |  |  |
Building and Land Improvements | 3,704 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 8,275 |  |  |
Building and Land Improvements | 3,704 |  |  |
Total | 11,979 |  |  |
Sentry Gateway - T [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 14,020 |  |  |
Building and Land Improvements | 38,804 |  |  |
Costs Capitalized Subsequent to Acquisition | 13 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 14,020 |  |  |
Building and Land Improvements | 38,817 |  |  |
Total | 52,837 |  |  |
Accumulated Depreciation | (10,561) |  |  |
Sentry Gateway - V [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 1,066 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 1,066 |  |  |
Total | 1,066 |  |  |
Accumulated Depreciation | (241) |  |  |
Sentry Gateway - W [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 1,884 |  |  |
Costs Capitalized Subsequent to Acquisition | 71 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 0 |  |  |
Building and Land Improvements | 1,955 |  |  |
Total | 1,955 |  |  |
Accumulated Depreciation | (392) |  |  |
Sentry Gateway - X [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,964 |  |  |
Building and Land Improvements | 21,178 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,964 |  |  |
Building and Land Improvements | 21,178 |  |  |
Total | 23,142 |  |  |
Accumulated Depreciation | (3,787) |  |  |
Sentry Gateway - Y [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,964 |  |  |
Building and Land Improvements | 21,298 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,964 |  |  |
Building and Land Improvements | 21,298 |  |  |
Total | 23,262 |  |  |
Accumulated Depreciation | (3,810) |  |  |
Sentry Gateway - Z [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 1,964 |  |  |
Building and Land Improvements | 30,573 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 1,964 |  |  |
Building and Land Improvements | 30,573 |  |  |
Total | 32,537 |  |  |
Accumulated Depreciation | (2,144) |  |  |
Westfields - Park Center [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 16,418 |  |  |
Building and Land Improvements | 11,264 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 16,418 |  |  |
Building and Land Improvements | 11,264 |  |  |
Total | 27,682 |  |  |
Westfields Corporate Center [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 7,141 |  |  |
Building and Land Improvements | 1,649 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 7,141 |  |  |
Building and Land Improvements | 1,649 |  |  |
Total | 8,790 |  |  |
Other Developments, including intercompany eliminations [Member] |  |  |  |
Initial Cost |  |  |  |
Land | 4 |  |  |
Building and Land Improvements | 283 |  |  |
Costs Capitalized Subsequent to Acquisition | 256 |  |  |
Gross Amounts Carried At Close of Period |  |  |  |
Land | 4 |  |  |
Building and Land Improvements | 539 |  |  |
Total | 543 |  |  |
Accumulated Depreciation | (58) |  |  |
Fair value measurement on a nonrecurring basis [Member] | Real Estate Held [Member] |  |  |  |
Additional information |  |  |  |
Impairment losses | 13,700 |  |  |
Fair value measurement on a nonrecurring basis [Member] | Real Estate Investment Properties, Net [Member] |  |  |  |
Additional information |  |  |  |
Impairment losses | $ 15,100 |  |  |

X
- Definition Debt Instrument, Unamortized Discount (Premium) and Deferred Financing Costs, Net + References No definition available. + Details
Name: | ofc_DebtInstrumentUnamortizedDiscountPremiumandDeferredFinancingCostsNet
Namespace Prefix: | ofc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2420-110228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 + Details
Name: | us-gaap_AssetImpairmentCharges
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of accumulated depreciation pertaining to real estate investments for entities with a substantial portion of business acquiring and holding investment real estate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28.FN4) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 + Details
Name: | us-gaap_RealEstateAccumulatedDepreciation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lien or mortgage outstanding on real estate investment properties for entities with a substantial portion of business acquiring and holding investment real estate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationAmountOfEncumbrances
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before accumulated depreciation of buildings and improvements for entities with a substantial portion of business acquiring and holding investment real estate. Excludes real estate not held as an investment or interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfBuildingsAndImprovements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of land for entities with a substantial portion of business acquiring and holding investment real estate. Excludes real estate not held as an investment or interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLand
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationCarryingAmountOfLandAndBuildingsAndImprovementsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of carrying costs of properties that were capitalized after acquisition, for example, but not limited to, real estate taxes and insurance for entities with a substantial portion of business acquiring and holding investment real estate. Excludes initial purchase price and improvements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationCostsCapitalizedSubsequentToAcquisitionCarryingCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationInitialCostAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Initial cost of buildings and improvements for entities with a substantial portion of business acquiring and holding investment real estate. Excludes real estate not held as an investment or interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfBuildingsAndImprovements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Initial cost of land for entities with a substantial portion of business acquiring and holding investment real estate. Excludes real estate not held as an investment or interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationInitialCostOfLand
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Useful life on which depreciation was computed for entities with a substantial portion of business acquiring and holding investment real estate, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationOtherRequiredDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Cost basis of real estate investments for federal income tax purposes for entities with a substantial portion of business acquiring and holding investment real estate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28.FN6) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 + Details
Name: | us-gaap_RealEstateFederalIncomeTaxBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, before accumulated depreciation, of real estate investments for entities with a substantial portion of business acquiring and holding investment real estate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28.4) -URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024 + Details
Name: | us-gaap_RealEstateGrossAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_TermLoanFacilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ofc_FixedRateSecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number100LightStreetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1000RedstoneGatewayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1100RedstoneGatewayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number114NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number11751MeadowvilleLaneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1200RedstoneGatewayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1201MStreetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1201WintersonRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number122012ThStreetSeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1243WintersonRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number131NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number132NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number133NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number134NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1340AshtonRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number13450SunriseValleyRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number13454SunriseValleyRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number135NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1362MellonRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number13857MclearenRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number140NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number141NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number14280ParkMeadowDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1460DorseyRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number14840ConferenceCenterDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number14850ConferenceCenterDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number14900ConferenceCenterDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1501SouthClintonStreetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number15049ConferenceCenterDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number15059ConferenceCenterDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1550WestNurseryRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1560WestNurseryRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1610WestNurseryRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1616WestNurseryRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1622WestNurseryRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number16442CommerceDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number16480CommerceDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number16501CommerceDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number16539CommerceDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number16541CommerceDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number16543CommerceDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1751PinnacleDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number1753PinnacleDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number206ResearchBoulevardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number209ResearchBoulevardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number210ResearchBoulevardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number2100LStreetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number2100RideoutRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number22289ExplorationDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number22299ExplorationDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number22300ExplorationDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number22309ExplorationDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number23535CottonwoodParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number250WPrattStMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number2500RivaRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number2600ParkTowerDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number2691TechnologyDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number2701TechnologyDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number2711TechnologyDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number2720TechnologyDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number2721TechnologyDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number2730HerculesRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number30LightStreetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number300SentinelDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number302SentinelDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number304SentinelDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number306SentinelDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number308SentinelDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number310SentinelWayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number310BridgeStreetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number312SentinelWayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number314SentinelWayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number316SentinelWayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number318SentinelWayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number320SentinelWayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number322SentinelWayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number324SentinelWayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number4000MarketStreetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number4100MarketStreetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number410NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number420NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number430NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number44408PecanCourtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number44414PecanCourtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number44417PecanCourtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number44420PecanCourtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number44425PecanCourtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number45310AbellHouseLaneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number46579ExpeditionDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number46591ExpeditionDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number4851StonecroftBoulevardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number540NationalBusinessParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number5520ResearchParkDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number5522ResearchParkDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number5801UniversityResearchCourtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number5825UniversityResearchCourtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number5850UniversityResearchCourtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6700AlexanderBellDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6708AlexanderBellDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6711ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6716AlexanderBellDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6721ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6724AlexanderBellDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6731ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6740AlexanderBellDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6741ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6750AlexanderBellDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6760AlexanderBellDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6940ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number6950ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7000ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7005ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7015AlbertEinsteinDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7061ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7063ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7065ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7067ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7125ColumbiaGatewayDriveLandMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7125ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7130ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7134ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7138ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7142ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7150ColumbiaGatewayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7150RiverwoodDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7160RiverwoodDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7170RiverwoodDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7175RiverwoodDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7200RedstoneGatewayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7200RiverwoodRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7205RiverwoodDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7272ParkCircleDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7318ParkwayDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7400RedstoneGatewayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7467RidgeRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7740MilestoneParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7770BacklickRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number7880MilestoneParkwayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number8621RobertFultonDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number8661RobertFultonDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number8671RobertFultonDriveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number870ElkridgeLandingRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number891ElkridgeLandingRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number901ElkridgeLandingRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number911ElkridgeLandingRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number938ElkridgeLandingRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number939ElkridgeLandingRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number940ElkridgeLandingRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Number9651HornbakerRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_ArundelPreserveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_BethlehemTechnologyParkDC18Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_BethlehemTechnologyParkDC19Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_BethlehemTechnologyParkDC20Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_BethlehemTechnologyParkDC23Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_BLC1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_BLC2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_CantonCrossingLandMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_CantonCrossingUtilDistrCtrMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_ColumbiaGatewaySouthridgeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_DahlgrenTechnologyCenterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_ExpeditionViiMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_InnovationParkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_MSquareResearchParkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_MRLandMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_NationalBusinessParkNorthMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_NorthGateBusinessParkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_NorthwestCrossroadsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_NOVAOfficeAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_NOVAOfficeBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_NOVAOfficeDMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_OldAnnapolisRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_ParagonParkDC21Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_ParagonParkDC22Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_PatriotPointDC15Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_PatriotPointDC16Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_PatriotPointDC17Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_PatriotRidgeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_RedstoneGatewayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_Route15BiggsFordRoadMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_SentryGatewayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_SentryGatewayTMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_SentryGatewayVMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_SentryGatewayWMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_SentryGatewayXMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_SentryGatewayYMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_SentryGatewayZMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_WestfieldsParkCenterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_WestfieldsCorporateCenterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ofc_OtherDevelopmentsIncludingIntercompanyEliminationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstatePropertiesAxis=ofc_RealEstateHeldMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ofc_AssetsbyTypeAxis=ofc_RealEstateInvestmentPropertiesNetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |