Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	$ 164,318	$ 128,681	$ 262,431	$ 304,682
Preferred Stock Dividends / Distributions	(2,625)	(2,625)	(5,250)	(5,250)
Noncontrolling interest-common units of the Operating Partnership	(19,036)	(14,859)	(30,627)	(35,311)
Noncontrolling interest in property partnerships	(17,482)	(14,400)	(36,312)	(31,634)
Interest expense	(102,357)	(92,204)	(203,366)	(182,424)
Company's share of net operating from joint ventures	(454,301)	(406,678)	(902,016)	(808,137)
Depreciation and amortization expense	(177,411)	(156,417)	(342,005)	(322,214)
Transaction costs	(417)	(474)	(877)	(495)
General and administrative expense	(35,071)	(28,468)	(76,833)	(64,362)
Gains from investments in securities	(1,165)	(505)	(4,134)	(379)
Interest and other income	(3,615)	(2,579)	(7,368)	(4,227)
Income from unconsolidated joint ventures	(47,964)	(769)	(48,177)	(1,230)
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	164,318	128,681	262,431	304,682
Preferred Stock Dividends / Distributions	2,625	2,625	5,250	5,250
Noncontrolling interest-common units of the Operating Partnership	19,036	14,859	30,627	35,311
Noncontrolling interest in property partnerships	17,482	14,400	36,312	31,634
Interest expense	102,357	92,204	203,366	182,424
Impairment loss	0	0	24,038	0
Depreciation and amortization expense	177,411	156,417	342,005	322,214
Transaction costs	417	474	877	495
Payroll and related costs from management service contracts	2,403	1,970	5,798	4,855
General and administrative expense	35,071	28,468	76,833	64,362
Gains from investments in securities	1,165	505	4,134	379
Interest and other income	3,615	2,579	7,368	4,227
(Losses) gains on sales of real estate	1,686	18,292	781	114,689
Income from unconsolidated joint ventures	47,964	769	48,177	1,230
Direct reimbursement of payroll and related costs from management service contracts	2,403	1,970	5,798	4,855
Company's Share of Net Operating Income	433,454	379,856	859,433	751,466
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	185,715	145,961	299,097	346,868
Preferred Stock Dividends / Distributions	(2,625)	(2,625)	(5,250)	(5,250)
Noncontrolling interest in property partnerships	(17,482)	(14,400)	(36,312)	(31,634)
Interest expense	(102,357)	(92,204)	(203,366)	(182,424)
Depreciation and amortization expense	(175,199)	(154,474)	(337,881)	(318,327)
Transaction costs	(417)	(474)	(877)	(495)
Payroll and related costs from management service contracts			(5,798)	(4,855)
General and administrative expense	(35,071)	(28,468)	(76,833)	(64,362)
Gains from investments in securities	(1,165)	(505)	(4,134)	(379)
Interest and other income	(3,615)	(2,579)	(7,368)	(4,227)
Income from unconsolidated joint ventures	(47,964)	(769)	(48,177)	(1,230)
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	185,715	145,961	299,097	346,868
Preferred Stock Dividends / Distributions	2,625	2,625	5,250	5,250
Noncontrolling interest in property partnerships	17,482	14,400	36,312	31,634
Interest expense	102,357	92,204	203,366	182,424
Impairment loss	0	0	22,272	0
Depreciation and amortization expense	175,199	154,474	337,881	318,327
Transaction costs	417	474	877	495
Payroll and related costs from management service contracts	2,403	1,970	5,798	4,855
General and administrative expense	35,071	28,468	76,833	64,362
Gains from investments in securities	1,165	505	4,134	379
Interest and other income	3,615	2,579	7,368	4,227
(Losses) gains on sales of real estate	1,835	18,770	930	117,677
Income from unconsolidated joint ventures	47,964	769	48,177	1,230
Direct reimbursement of payroll and related costs from management service contracts	2,403	1,970	5,798	4,855
Company's Share of Net Operating Income	433,454	379,856	859,433	751,466
Development and Management Services [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Payroll and related costs from management service contracts	(2,403)	(1,970)	(5,798)	(4,855)
Direct reimbursement of payroll and related costs from management service contracts	(9,986)	(9,305)	(19,263)	(17,710)
Development and Management Services [Member] \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Direct reimbursement of payroll and related costs from management service contracts	9,986	9,305	19,263	17,710
Development and Management Services [Member] \| Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Payroll and related costs from management service contracts	(2,403)	(1,970)
Direct reimbursement of payroll and related costs from management service contracts	(9,986)	(9,305)	(19,263)	(17,710)
Development and Management Services [Member] \| Boston Properties Limited Partnership \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Direct reimbursement of payroll and related costs from management service contracts	9,986	9,305	19,263	17,710
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 from joint ventures	45,562	43,049	92,647	88,958
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 from joint ventures	45,562	43,049	92,647	88,958
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 from joint ventures	45,562	43,049	92,647	88,958
Unconsolidated Joint Ventures [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest expense	(20,803)	(14,708)	(41,560)	(29,132)
Company's share of net operating from joint ventures	(24,715)	(16,227)	(50,064)	(32,287)
Depreciation and amortization expense	(24,818)	(14,527)	(53,464)	(29,252)
Income from unconsolidated joint ventures	(47,964)	(769)	(48,177)	(1,230)
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 from joint ventures	(24,715)	(16,227)	(50,064)	(32,287)
Unconsolidated Joint Ventures [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 from joint ventures	$ (24,715)	$ (16,227)	$ (50,064)	$ (32,287)

Company's Share of Net Operating Income

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