Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	$ 89,854	$ 107,771	$ 854,541	$ 370,200
Preferred dividends / distributions	(2,625)	(2,625)	(7,875)	(7,875)
Noncontrolling interest-common units of the Operating Partnership	(10,020)	(12,504)	(97,090)	(43,133)
Noncontrolling interest in property partnerships	(15,561)	(18,470)	(34,280)	(54,782)
Interest expense	(110,993)	(106,471)	(319,726)	(309,837)
Loss from early extinguishment of debt	0	(28,010)	0	(28,010)
Company's share of net operating income from joint ventures	(421,666)	(456,475)	(1,295,723)	(1,358,491)
Depreciation and amortization expense	(166,456)	(165,862)	(515,738)	(507,867)
Transaction costs	(307)	(538)	(1,254)	(1,415)
General and administrative expense	(27,862)	(31,147)	(102,059)	(107,980)
Gains from investments in securities	(1,858)	(106)	(965)	(4,240)
Interest and other income (loss)	45	(7,178)	(4,277)	(14,546)
Gains on sales of real estate	209	15	(613,723)	(766)
Income (loss) from unconsolidated joint ventures	6,873	649	5,410	(47,528)
Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	89,854	107,771	854,541	370,200
Preferred dividends / distributions	2,625	2,625	7,875	7,875
Noncontrolling interest-common units of the Operating Partnership	10,020	12,504	97,090	43,133
Noncontrolling interest in property partnerships	15,561	18,470	34,280	54,782
Interest expense	110,993	106,471	319,726	309,837
Loss from early extinguishment of debt	0	28,010	0	28,010
Impairment losses	0	0	0	24,038
Depreciation and amortization expense	166,456	165,862	515,738	507,867
Transaction costs	307	538	1,254	1,415
Operating expense	2,896	2,429	8,617	8,227
General and administrative expense	27,862	31,147	102,059	107,980
Gains from investments in securities	1,858	106	965	4,240
Interest and other income (loss)	(45)	7,178	4,277	14,546
Gains on sales of real estate	(209)	(15)	613,723	766
Income (loss) from unconsolidated joint ventures	(6,873)	(649)	(5,410)	47,528
Other revenue	2,896	2,429	8,617	8,227
Net Operating Income	404,444	433,291	1,255,082	1,292,724
Unconsolidated Joint Ventures [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest expense	(25,481)	(20,483)	(71,370)	(62,043)
Company's share of net operating income from joint ventures	(24,938)	(23,065)	(81,607)	(73,129)
Depreciation and amortization expense	(35,810)	(23,477)	(105,235)	(76,941)
Gains on sales of real estate	0	812	(11,720)	(33,760)
Income (loss) from unconsolidated joint ventures	6,873	649	5,410	(47,528)
Unconsolidated Joint Ventures [Member] \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	24,938	23,065	81,607	73,129
Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	101,624	122,117	969,932	421,214
Preferred dividends / distributions	(2,625)	(2,625)	(7,875)	(7,875)
Noncontrolling interest in property partnerships	(15,561)	(18,470)	(34,280)	(54,782)
Interest expense	(110,993)	(106,471)	(319,726)	(309,837)
Loss from early extinguishment of debt	0	(28,010)	0	(28,010)
Depreciation and amortization expense	(164,706)	(164,020)	(510,400)	(501,901)
Transaction costs	(307)	(538)	(1,254)	(1,415)
General and administrative expense	(27,862)	(31,147)	(102,059)	(107,980)
Gains from investments in securities	(1,858)	(106)	(965)	(4,240)
Interest and other income (loss)	45	(7,178)	(4,277)	(14,546)
Gains on sales of real estate	209	15	(626,686)	(915)
Income (loss) from unconsolidated joint ventures	6,873	649	5,410	(47,528)
Boston Properties Limited Partnership \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	101,624	122,117	969,932	421,214
Preferred dividends / distributions	2,625	2,625	7,875	7,875
Noncontrolling interest in property partnerships	15,561	18,470	34,280	54,782
Interest expense	110,993	106,471	319,726	309,837
Loss from early extinguishment of debt	0	28,010	0	28,010
Impairment losses	0	0	0	22,272
Depreciation and amortization expense	164,706	164,020	510,400	501,901
Transaction costs	307	538	1,254	1,415
Operating expense	2,896	2,429	8,617	8,227
General and administrative expense	27,862	31,147	102,059	107,980
Gains from investments in securities	1,858	106	965	4,240
Interest and other income (loss)	(45)	7,178	4,277	14,546
Gains on sales of real estate	(209)	(15)	626,686	915
Income (loss) from unconsolidated joint ventures	(6,873)	(649)	(5,410)	47,528
Other revenue	2,896	2,429	8,617	8,227
Net Operating Income	404,444	433,291	1,255,082	1,292,724
Management Service [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	(7,281)	(10,303)	(23,285)	(29,566)
Management Service [Member] \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	7,281	10,303	23,285	29,566
Management Service [Member] \| Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating expense	(2,896)	(2,429)	(8,617)	(8,227)
Other revenue	(7,281)	(10,303)	(23,285)	(29,566)
Management Service [Member] \| Boston Properties Limited Partnership \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other revenue	7,281	10,303	23,285	29,566
Noncontrolling interest - property partnerships [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	42,160	46,249	122,248	138,896
Noncontrolling interest - property partnerships [Member] \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	42,160	46,249	122,248	138,896
Noncontrolling interest - property partnerships [Member] \| Boston Properties Limited Partnership \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	$ 42,160	$ 46,249	$ 122,248	$ 138,896

The net result for the period of deducting property operating expenses from property operating revenues.

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