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Segment Information (Schedule Of Segment Reporting By Geographic Area And Property Type) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Class A Office | [1] | $ 2,678,795 | $ 2,824,634 | $ 2,590,659
Rental Revenue: Residential | [1] | 38,146 | 36,914 | 22,551
Rental Revenue Total | [1] | $ 2,724,419 | $ 2,910,137 | $ 2,662,328
Rental Revenue: % of Grand Totals | [1] | 100.00% | 100.00% | 100.00%
Rental Expenses: Class A Office |  | $ 998,469 | $ 1,034,025 | $ 966,547
Rental Expenses: Residential |  | 18,739 | 15,985 | 12,604
Rental Expenses: Total |  | $ 1,030,344 | $ 1,084,014 | $ 1,013,014
Rental Expenses: % Of Grand Totals |  | 100.00% | 100.00% | 100.00%
Net Operating Income |  | $ 1,694,075 | $ 1,826,123 | $ 1,649,314
Net Operating Income: % of Grand Totals |  | 100.00% | 100.00% | 100.00%
Company's Share of Net Operating Income: % of Grand Totals |  | 100.00% | 100.00% | 100.00%
Total revenue |  | $ 2,765,686 | $ 2,960,562 | $ 2,717,076
Boston [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Class A Office | [1] | 897,915 | 895,098 | 838,341
Rental Revenue: Residential | [1] | 13,616 | 13,786 | 6,694
Rental Revenue Total | [1] | $ 919,009 | $ 957,473 | $ 894,153
Rental Revenue: % of Grand Totals | [1] | 33.73% | 32.90% | 33.59%
Rental Expenses: Class A Office |  | $ 318,509 | $ 322,282 | $ 315,653
Rental Expenses: Residential |  | 5,378 | 5,071 | 3,632
Rental Expenses: Total |  | $ 337,023 | $ 361,357 | $ 353,148
Rental Expenses: % Of Grand Totals |  | 32.71% | 33.34% | 34.86%
Net Operating Income |  | $ 581,986 | $ 596,116 | $ 541,005
Net Operating Income: % of Grand Totals |  | 34.35% | 32.64% | 32.80%
Company's Share of Net Operating Income: % of Grand Totals |  | 33.88% | 32.27% | 32.86%
Los Angeles [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Class A Office | [1] | $ 0 | $ 0 | $ 0
Rental Revenue: Residential | [1] | 0 | 0 | 0
Rental Revenue Total | [1] | $ 0 | $ 0 | $ 0
Rental Revenue: % of Grand Totals | [1] | 0.00% | 0.00% | 0.00%
Rental Expenses: Class A Office |  | $ 0 | $ 0 | $ 0
Rental Expenses: Residential |  | 0 | 0 | 0
Rental Expenses: Total |  | $ 0 | $ 0 | $ 0
Rental Expenses: % Of Grand Totals |  | 0.00% | 0.00% | 0.00%
Net Operating Income |  | $ 0 | $ 0 | $ 0
Net Operating Income: % of Grand Totals |  | 0.00% | 0.00% | 0.00%
Company's Share of Net Operating Income: % of Grand Totals |  | 3.56% | 3.53% | 2.75%
New York [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Class A Office | [1] | $ 935,966 | $ 1,011,912 | $ 959,050
Rental Revenue: Residential | [1] | 0 | 0 | 0
Rental Revenue Total | [1] | $ 935,966 | $ 1,011,912 | $ 959,050
Rental Revenue: % of Grand Totals | [1] | 34.36% | 34.78% | 36.02%
Rental Expenses: Class A Office |  | $ 384,753 | $ 389,532 | $ 377,992
Rental Expenses: Residential |  | 0 | 0 | 0
Rental Expenses: Total |  | $ 384,753 | $ 389,532 | $ 377,992
Rental Expenses: % Of Grand Totals |  | 37.35% | 35.93% | 37.32%
Net Operating Income |  | $ 551,213 | $ 622,380 | $ 581,058
Net Operating Income: % of Grand Totals |  | 32.54% | 34.09% | 35.23%
Company's Share of Net Operating Income: % of Grand Totals |  | 26.12% | 27.77% | 28.63%
San Francisco [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Class A Office | [1] | $ 508,327 | $ 533,189 | $ 397,180
Rental Revenue: Residential | [1] | 155 | 0 | 0
Rental Revenue Total | [1] | $ 508,482 | $ 533,189 | $ 397,180
Rental Revenue: % of Grand Totals | [1] | 18.66% | 18.32% | 14.92%
Rental Expenses: Class A Office |  | $ 163,156 | $ 177,994 | $ 130,016
Rental Expenses: Residential |  | 2,261 | 0 | 0
Rental Expenses: Total |  | $ 165,417 | $ 177,994 | $ 130,016
Rental Expenses: % Of Grand Totals |  | 16.05% | 16.42% | 12.83%
Net Operating Income |  | $ 343,065 | $ 355,195 | $ 267,164
Net Operating Income: % of Grand Totals |  | 20.25% | 19.45% | 16.20%
Company's Share of Net Operating Income: % of Grand Totals |  | 22.02% | 20.39% | 17.22%
Washington, DC [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Class A Office | [1] | $ 336,587 | $ 384,435 | $ 396,088
Rental Revenue: Residential | [1] | 24,375 | 23,128 | 15,857
Rental Revenue Total | [1] | $ 360,962 | $ 407,563 | $ 411,945
Rental Revenue: % of Grand Totals | [1] | 13.25% | 14.00% | 15.47%
Rental Expenses: Class A Office |  | $ 132,051 | $ 144,217 | $ 142,886
Rental Expenses: Residential |  | 11,100 | 10,914 | 8,972
Rental Expenses: Total |  | $ 143,151 | $ 155,131 | $ 151,858
Rental Expenses: % Of Grand Totals |  | 13.89% | 14.31% | 14.99%
Net Operating Income |  | $ 217,811 | $ 252,432 | $ 260,087
Net Operating Income: % of Grand Totals |  | 12.86% | 13.82% | 15.77%
Company's Share of Net Operating Income: % of Grand Totals |  | 14.42% | 16.04% | 18.54%
Hotel [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | [1] | $ 7,478 | $ 48,589 | $ 49,118
Operating expense |  | 13,136 | 34,004 | 33,863
Hotel [Member] | Boston [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | [1] | 7,478 | 48,589 | 49,118
Operating expense |  | 13,136 | 34,004 | 33,863
Hotel [Member] | Los Angeles [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | [1] | 0 | 0 | 0
Operating expense |  | 0 | 0 | 0
Hotel [Member] | New York [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | [1] | 0 | 0 | 0
Operating expense |  | 0 | 0 | 0
Hotel [Member] | San Francisco [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | [1] | 0 | 0 | 0
Operating expense |  | 0 | 0 | 0
Hotel [Member] | Washington, DC [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | [1] | 0 | 0 | 0
Operating expense |  | 0 | 0 | 0
Noncontrolling interest - property partnerships [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | (162,887) | (183,989) | (177,365)
Noncontrolling interest - property partnerships [Member] | Boston [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | (41,849) | (40,109) | (33,862)
Noncontrolling interest - property partnerships [Member] | Los Angeles [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 0 | 0 | 0
Noncontrolling interest - property partnerships [Member] | New York [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | (121,038) | (143,432) | (143,562)
Noncontrolling interest - property partnerships [Member] | San Francisco [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 0 | (448) | 59
Noncontrolling interest - property partnerships [Member] | Washington, DC [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 0 | 0 | 0
Unconsolidated Joint Ventures [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 94,943 | 97,716 | 79,893
Total revenue | [2] | 319,560 | 322,817 | 271,951
Unconsolidated Joint Ventures [Member] | Boston [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 10,765 | 5,494 | 2,866
Unconsolidated Joint Ventures [Member] | Los Angeles [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 57,907 | 61,338 | 42,750
Unconsolidated Joint Ventures [Member] | New York [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | (5,326) | 4,174 | 6,590
Unconsolidated Joint Ventures [Member] | San Francisco [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 14,928 | 0 | 0
Unconsolidated Joint Ventures [Member] | Washington, DC [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 16,669 | 26,710 | 27,687
Company's Share [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 1,626,131 | 1,739,850 | 1,551,842
Company's Share [Member] | Boston [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 550,902 | 561,501 | 510,009
Company's Share [Member] | Los Angeles [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 57,907 | 61,338 | 42,750
Company's Share [Member] | New York [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 424,849 | 483,122 | 444,086
Company's Share [Member] | San Francisco [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | 357,993 | 354,747 | 267,223
Company's Share [Member] | Washington, DC [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income |  | $ 234,480 | $ 279,142 | $ 287,774
[1] | Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.
[2] | Includes straight-line rent adjustments of approximately $(10.1) million, $32.4 million and $15.9 million for the years ended December 31, 2020, 2019 and 2018, respectively. Due primarily to the impact of COVID-19, for the year ended December 31, 2020, write-offs of accounts receivable and accrued rent balances totaled approximately $51.7 million.

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