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Segment Information (Schedule Of Segment Reporting By Geographic Area And Property Type) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Office | $ 832,365 | $ 821,609 | $ 2,489,563 | $ 2,442,675
Rental Revenue: Residential | 12,845 | 12,117 | 37,725 | 37,027
Rental Revenue Total | $ 858,372 | $ 848,808 | $ 2,564,820 | $ 2,517,782
Rental Revenue: % of Grand Totals | 100.00% | 100.00% | 100.00% | 100.00%
Rental Expenses: Office | $ 325,641 | $ 321,909 | $ 976,806 | $ 946,067
Rental Expenses: Residential | 6,095 | 5,988 | 18,570 | 17,413
Rental Expenses: Total | $ 341,364 | $ 337,730 | $ 1,021,934 | $ 989,167
Rental Expenses: % Of Grand Totals | 100.00% | 100.00% | 100.00% | 100.00%
Net Operating Income | $ 517,008 | $ 511,078 | $ 1,542,886 | $ 1,528,615
Net Operating Income: % of Grand Totals | 100.00% | 100.00% | 100.00% | 100.00%
Company's Share of Net Operating Income: % of Grand Totals | 100.00% | 100.00% | 100.00% | 100.00%
Boston [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Office | $ 302,589 | $ 300,613 | $ 911,700 | $ 866,431
Rental Revenue: Residential | 4,633 | 4,219 | 13,162 | 12,687
Rental Revenue Total | $ 320,384 | $ 319,914 | $ 962,394 | $ 917,198
Rental Revenue: % of Grand Totals | 37.32% | 37.69% | 37.52% | 36.42%
Rental Expenses: Office | $ 113,087 | $ 107,876 | $ 341,207 | $ 321,955
Rental Expenses: Residential | 1,943 | 1,621 | 5,424 | 4,757
Rental Expenses: Total | $ 124,658 | $ 119,330 | $ 373,189 | $ 352,399
Rental Expenses: % Of Grand Totals | 36.52% | 35.34% | 36.52% | 35.62%
Net Operating Income | $ 195,726 | $ 200,584 | $ 589,205 | $ 564,799
Net Operating Income: % of Grand Totals | 37.85% | 39.25% | 38.19% | 36.96%
Company's Share of Net Operating Income: % of Grand Totals | 37.89% | 39.89% | 38.26% | 37.51%
Los Angeles [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Office | $ 17,735 | $ 18,661 | $ 52,516 | $ 57,534
Rental Revenue: Residential | 0 | 0 | 0 | 0
Rental Revenue Total | $ 17,735 | $ 18,661 | $ 52,516 | $ 57,534
Rental Revenue: % of Grand Totals | 2.07% | 2.20% | 2.05% | 2.29%
Rental Expenses: Office | $ 1,613 | $ 7,344 | $ 15,059 | $ 20,678
Rental Expenses: Residential | 0 | 0 | 0 | 0
Rental Expenses: Total | $ 1,613 | $ 7,344 | $ 15,059 | $ 20,678
Rental Expenses: % Of Grand Totals | 0.47% | 2.17% | 1.47% | 2.09%
Net Operating Income | $ 16,122 | $ 11,317 | $ 37,457 | $ 36,856
Net Operating Income: % of Grand Totals | 3.12% | 2.21% | 2.43% | 2.41%
Company's Share of Net Operating Income: % of Grand Totals | 4.64% | 3.64% | 3.96% | 3.89%
New York [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Office | $ 263,212 | $ 258,295 | $ 790,726 | $ 780,909
Rental Revenue: Residential | 0 | 0 | 0 | 0
Rental Revenue Total | $ 263,212 | $ 258,295 | $ 790,726 | $ 780,909
Rental Revenue: % of Grand Totals | 30.66% | 30.43% | 30.83% | 31.02%
Rental Expenses: Office | $ 113,951 | $ 111,419 | $ 338,588 | $ 327,376
Rental Expenses: Residential | 0 | 0 | 0 | 0
Rental Expenses: Total | $ 113,951 | $ 111,419 | $ 338,588 | $ 327,376
Rental Expenses: % Of Grand Totals | 33.38% | 32.99% | 33.13% | 33.10%
Net Operating Income | $ 149,261 | $ 146,876 | $ 452,138 | $ 453,533
Net Operating Income: % of Grand Totals | 28.87% | 28.74% | 29.30% | 29.67%
Company's Share of Net Operating Income: % of Grand Totals | 23.33% | 23.41% | 23.81% | 24.21%
San Francisco [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Office | $ 127,441 | $ 128,929 | $ 378,629 | $ 393,252
Rental Revenue: Residential | 3,316 | 3,152 | 10,174 | 10,428
Rental Revenue Total | $ 130,757 | $ 132,081 | $ 388,803 | $ 403,680
Rental Revenue: % of Grand Totals | 15.23% | 15.56% | 15.16% | 16.03%
Rental Expenses: Office | $ 53,077 | $ 52,410 | $ 151,261 | $ 148,020
Rental Expenses: Residential | 1,982 | 2,346 | 6,926 | 6,733
Rental Expenses: Total | $ 55,059 | $ 54,756 | $ 158,187 | $ 154,753
Rental Expenses: % Of Grand Totals | 16.13% | 16.21% | 15.48% | 15.64%
Net Operating Income | $ 75,698 | $ 77,325 | $ 230,616 | $ 248,927
Net Operating Income: % of Grand Totals | 14.64% | 15.13% | 14.95% | 16.28%
Company's Share of Net Operating Income: % of Grand Totals | 16.09% | 16.37% | 16.41% | 17.65%
Seattle |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Office | $ 14,394 | $ 10,821 | $ 38,497 | $ 32,251
Rental Revenue: Residential | 0 | 0 | 0 | 0
Rental Revenue Total | $ 14,394 | $ 10,821 | $ 38,497 | $ 32,251
Rental Revenue: % of Grand Totals | 1.68% | 1.27% | 1.50% | 1.28%
Rental Expenses: Office | $ 3,304 | $ 3,382 | $ 9,286 | $ 9,753
Rental Expenses: Residential | 0 | 0 | 0 | 0
Rental Expenses: Total | $ 3,304 | $ 3,382 | $ 9,286 | $ 9,753
Rental Expenses: % Of Grand Totals | 0.97% | 1.00% | 0.91% | 0.99%
Net Operating Income | $ 11,090 | $ 7,439 | $ 29,211 | $ 22,498
Net Operating Income: % of Grand Totals | 2.15% | 1.46% | 1.89% | 1.47%
Company's Share of Net Operating Income: % of Grand Totals | 2.75% | 1.87% | 2.44% | 1.89%
Washington, DC [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Rental Revenue: Office | $ 106,994 | $ 104,290 | $ 317,495 | $ 312,298
Rental Revenue: Residential | 4,896 | 4,746 | 14,389 | 13,912
Rental Revenue Total | $ 111,890 | $ 109,036 | $ 331,884 | $ 326,210
Rental Revenue: % of Grand Totals | 13.04% | 12.85% | 12.94% | 12.96%
Rental Expenses: Office | $ 40,609 | $ 39,478 | $ 121,405 | $ 118,285
Rental Expenses: Residential | 2,170 | 2,021 | 6,220 | 5,923
Rental Expenses: Total | $ 42,779 | $ 41,499 | $ 127,625 | $ 124,208
Rental Expenses: % Of Grand Totals | 12.53% | 12.29% | 12.49% | 12.56%
Net Operating Income | $ 69,111 | $ 67,537 | $ 204,259 | $ 202,002
Net Operating Income: % of Grand Totals | 13.37% | 13.21% | 13.24% | 13.21%
Company's Share of Net Operating Income: % of Grand Totals | 15.30% | 14.82% | 15.12% | 14.85%
Hotel [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | $ 13,162 | $ 15,082 | $ 37,532 | $ 38,080
Operating expense | 9,628 | 9,833 | 26,558 | 25,687
Hotel [Member] | Boston [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | 13,162 | 15,082 | 37,532 | 38,080
Operating expense | 9,628 | 9,833 | 26,558 | 25,687
Hotel [Member] | Los Angeles [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | 0 | 0 | 0 | 0
Operating expense | 0 | 0 | 0 | 0
Hotel [Member] | New York [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | 0 | 0 | 0 | 0
Operating expense | 0 | 0 | 0 | 0
Hotel [Member] | San Francisco [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | 0 | 0 | 0 | 0
Operating expense | 0 | 0 | 0 | 0
Hotel [Member] | Seattle |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | 0 | 0 | 0 | 0
Operating expense | 0 | 0 | 0 | 0
Hotel [Member] | Washington, DC [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Other revenue | 0 | 0 | 0 | 0
Operating expense | 0 | 0 | 0 | 0
Noncontrolling interest - property partnerships [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | (51,504) | (44,487) | (152,768) | (138,448)
Noncontrolling interest - property partnerships [Member] | Boston [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | (16,574) | (10,823) | (47,603) | (32,803)
Noncontrolling interest - property partnerships [Member] | Los Angeles [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 0 | 0 | 0 | 0
Noncontrolling interest - property partnerships [Member] | New York [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | (34,930) | (33,664) | (105,165) | (105,645)
Noncontrolling interest - property partnerships [Member] | San Francisco [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 0 | 0 | 0 | 0
Noncontrolling interest - property partnerships [Member] | Seattle |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 0 | 0 | 0 | 0
Noncontrolling interest - property partnerships [Member] | Washington, DC [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 0 | 0 | 0 | 0
Unconsolidated Joint Ventures [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 30,675 | 31,919 | 94,386 | 98,936
Unconsolidated Joint Ventures [Member] | Boston [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 8,903 | 9,099 | 26,424 | 26,547
Unconsolidated Joint Ventures [Member] | Los Angeles [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 6,876 | 6,835 | 21,281 | 21,118
Unconsolidated Joint Ventures [Member] | New York [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 1,423 | 3,472 | 6,447 | 12,614
Unconsolidated Joint Ventures [Member] | San Francisco [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 4,146 | 4,285 | 12,925 | 13,850
Unconsolidated Joint Ventures [Member] | Seattle |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 2,545 | 1,899 | 7,079 | 5,713
Unconsolidated Joint Ventures [Member] | Washington, DC [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 6,782 | 6,329 | 20,230 | 19,094
Company's Share [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 496,179 | 498,510 | 1,484,504 | 1,489,103
Company's Share [Member] | Boston [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 188,055 | 198,860 | 568,026 | 558,543
Company's Share [Member] | Los Angeles [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 22,998 | 18,152 | 58,738 | 57,974
Company's Share [Member] | New York [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 115,754 | 116,684 | 353,420 | 360,502
Company's Share [Member] | San Francisco [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 79,844 | 81,610 | 243,541 | 262,777
Company's Share [Member] | Seattle |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | 13,635 | 9,338 | 36,290 | 28,211
Company's Share [Member] | Washington, DC [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net Operating Income | $ 75,893 | $ 73,866 | $ 224,489 | $ 221,096

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