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SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION (Details) - USD ($) | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
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REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Encumbrances | $ 0 |  |  |
Accumulated Depreciation | 366,349,000 | $ 423,417,000 | $ 424,487,000 | $ 538,717,000
Aggregate cost for Federal Income Tax purposes | 1,401,985 |  |  |
Real Estate Excluding Assets Held For Sale |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | 110,889,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 865,439,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 280,845,000 |  |  |
Historical Cost of Land | 110,298,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 1,146,875,000 |  |  |
Total | 1,257,173,000 |  |  |
Accumulated Depreciation | 366,349,000 |  |  |
Total Costs, Net of Accumulated Depreciation | 890,824,000 |  |  |
Park Ten, Houston, TX |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | 1,061,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 21,303,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 8,100,000 |  |  |
Historical Cost of Land | 565,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 29,899,000 |  |  |
Total | 30,464,000 |  |  |
Accumulated Depreciation | 15,649,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 14,815,000 |  |  |
Park Ten, Houston, TX | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Park Ten, Houston, TX | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
Addison, Addison, TX |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 4,325,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 48,040,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 13,860,000 |  |  |
Historical Cost of Land | 4,325,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 61,900,000 |  |  |
Total | 66,225,000 |  |  |
Accumulated Depreciation | 30,173,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 36,052,000 |  |  |
Addison, Addison, TX | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Addison, Addison, TX | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
Greenwood, Englewood, CO |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 3,100,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 30,201,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 11,584,000 |  |  |
Historical Cost of Land | 3,100,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 41,785,000 |  |  |
Total | 44,885,000 |  |  |
Accumulated Depreciation | 20,108,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 24,777,000 |  |  |
Greenwood, Englewood, CO | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Greenwood, Englewood, CO | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
Innsbrook, Glenn Allen, VA |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 5,000,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 40,216,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 14,199,000 |  |  |
Historical Cost of Land | 5,000,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 54,415,000 |  |  |
Total | 59,415,000 |  |  |
Accumulated Depreciation | 21,809,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 37,606,000 |  |  |
Innsbrook, Glenn Allen, VA | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Innsbrook, Glenn Allen, VA | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
Eldridge Green, Houston, TX |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 3,900,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 43,791,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 12,400,000 |  |  |
Historical Cost of Land | 3,900,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 56,191,000 |  |  |
Total | 60,091,000 |  |  |
Accumulated Depreciation | 23,906,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 36,185,000 |  |  |
Eldridge Green, Houston, TX | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Eldridge Green, Houston, TX | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
Liberty Plaza, Addison, TX |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 4,374,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 21,146,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 11,991,000 |  |  |
Historical Cost of Land | 4,279,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 33,232,000 |  |  |
Total | 37,511,000 |  |  |
Accumulated Depreciation | 15,314,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 22,197,000 |  |  |
Liberty Plaza, Addison, TX | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Liberty Plaza, Addison, TX | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
Park Ten II, Houston, TX |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 1,300,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 31,712,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 7,258,000 |  |  |
Historical Cost of Land | 1,300,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 38,970,000 |  |  |
Total | 40,270,000 |  |  |
Accumulated Depreciation | 16,870,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 23,400,000 |  |  |
Park Ten II, Houston, TX | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Park Ten II, Houston, TX | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
121 South Eight Street, Minneapolis, MN |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 4,444,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 15,214,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 30,378,000 |  |  |
Historical Cost of Land | 4,444,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 45,592,000 |  |  |
Total | 50,036,000 |  |  |
Accumulated Depreciation | 16,769,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 33,267,000 |  |  |
121 South Eight Street, Minneapolis, MN | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
121 South Eight Street, Minneapolis, MN | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
801 Marquette Avenue South, Minneapolis, MN |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 4,184,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 28,280,000 |  |  |
Historical Cost of Land | 4,184,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 28,280,000 |  |  |
Total | 32,464,000 |  |  |
Accumulated Depreciation | 7,216,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 25,248,000 |  |  |
801 Marquette Avenue South, Minneapolis, MN | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
801 Marquette Avenue South, Minneapolis, MN | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
Legacy Tennyson Center, Plano, TX |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 3,067,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 22,064,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 6,166,000 |  |  |
Historical Cost of Land | 3,067,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 28,230,000 |  |  |
Total | 31,297,000 |  |  |
Accumulated Depreciation | 9,713,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 21,584,000 |  |  |
Legacy Tennyson Center, Plano, TX | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Legacy Tennyson Center, Plano, TX | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
Westchase I & II, Houston, TX |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 8,491,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 121,508,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 24,026,000 |  |  |
Historical Cost of Land | 8,491,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 145,534,000 |  |  |
Total | 154,025,000 |  |  |
Accumulated Depreciation | 42,809,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 111,216,000 |  |  |
Westchase I & II, Houston, TX | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Westchase I & II, Houston, TX | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
1999 Broadway, Denver CO |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 16,334,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 137,726,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 43,291,000 |  |  |
Historical Cost of Land | 16,334,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 181,017,000 |  |  |
Total | 197,351,000 |  |  |
Accumulated Depreciation | 52,482,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 144,869,000 |  |  |
1999 Broadway, Denver CO | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
1999 Broadway, Denver CO | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
1001 17th Street, Denver, CO |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 17,413,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 165,058,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 37,227,000 |  |  |
Historical Cost of Land | 17,413,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 202,285,000 |  |  |
Total | 219,698,000 |  |  |
Accumulated Depreciation | 53,627,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 166,071,000 |  |  |
1001 17th Street, Denver, CO | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
1001 17th Street, Denver, CO | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
Plaza Seven, Minneapolis, MN |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 6,604,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 54,240,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 14,025,000 |  |  |
Historical Cost of Land | 6,604,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 68,265,000 |  |  |
Total | 74,869,000 |  |  |
Accumulated Depreciation | 16,243,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 58,626,000 |  |  |
Plaza Seven, Minneapolis, MN | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Plaza Seven, Minneapolis, MN | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
600 17th Street, Denver, Co |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 20,876,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 99,941,000 |  |  |
Costs Capitalized (Disposals) Subsequent to Acquisition | 18,060,000 |  |  |
Historical Cost of Land | 20,876,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 118,001,000 |  |  |
Total | 138,877,000 |  |  |
Accumulated Depreciation | 23,320,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 115,557,000 |  |  |
600 17th Street, Denver, Co | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
600 17th Street, Denver, Co | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |
Monument Circle, Indianapolis, IN |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Initial cost of Land | $ 6,416,000 |  |  |
Initial cost of Buildings Improvements and Equipment | 13,279,000 |  |  |
Historical Cost of Land | 6,416,000 |  |  |
Historical Cost of Buildings Improvements and Equipment | 13,279,000 |  |  |
Total | 19,695,000 |  |  |
Accumulated Depreciation | 341,000 |  |  |
Total Costs, Net of Accumulated Depreciation | $ 19,354,000 |  |  |
Monument Circle, Indianapolis, IN | Minimum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 5 years |  |  |
Monument Circle, Indianapolis, IN | Maximum |  |  |  |
REAL ESTATE AND ACCUMULATED DEPRECIATION |  |  |  |
Depreciable Life Years | 39 years |  |  |

X
- Definition The carrying amount at which buildings improvements and equipments are carried at the end of the period. + References No definition available. + Details
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- Definition Gross amount at which land and buildings and improvements and equipments are carried at the end of the period for each property. + References No definition available. + Details
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- 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/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 28 -Paragraph Column B -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column B)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 + Details
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- 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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 28 -Paragraph Column B -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 28 -Paragraph Column C -Publisher SEC Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 28 -Paragraph Column D -Publisher SEC Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 28 -Paragraph Column E -Publisher SEC Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 28 -Paragraph Column F -Publisher SEC Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 28 -Paragraph Column G -Publisher SEC Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 28 -Paragraph Column H -Publisher SEC Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 28 -Paragraph Column I -Publisher SEC Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 28 -Footnote 2 -Publisher SEC Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column F)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column E)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column D)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column C)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column I)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column B)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column G)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column H)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Footnote 2)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 + Details
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- Definition Amount of cost capitalized subsequent to acquisition for real estate investment property, including, but not limited to, real estate tax and insurance, by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate. Excludes initial purchase price and improvement, and real estate not held as investment or interest. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column D)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 + Details
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