Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	$ 119,118	$ 117,337	$ 423,835	$ 348,086
Preferred Stock Dividends / Distributions	(2,625)	(2,625)	(7,875)	(7,875)
Noncontrolling interest-common units of the Operating Partnership	(13,852)	(13,402)	(49,128)	(40,350)
Noncontrolling interest in property partnerships	(14,850)	(14,340)	(46,484)	(33,967)
Interest expense	(95,366)	(92,032)	(277,790)	(282,709)
Depreciation and amortization expense	(157,996)	(152,164)	(480,210)	(463,288)
Transaction costs	(914)	(239)	(1,409)	(572)
Payroll and related costs from management services contracts	(2,516)	0	(7,371)	0
General and administrative expense	(29,677)	(25,792)	(94,039)	(84,319)
Gains from early extinguishments of debt	0	0	0	(14,354)
Gains from investments in securities	(1,075)	(944)	(1,454)	(2,716)
Interest and other income	(2,822)	(1,329)	(7,049)	(3,447)
Income (loss) from unconsolidated joint ventures	4,313	(843)	3,083	(7,035)
Direct reimbursements of payroll and related costs from management services contracts	(2,516)	0	(7,371)	0
Development and management services income	(15,253)	(10,811)	(32,963)	(24,648)
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	119,118	117,337	423,835	348,086
Preferred Stock Dividends / Distributions	2,625	2,625	7,875	7,875
Noncontrolling interest-common units of the Operating Partnership	13,852	13,402	49,128	40,350
Noncontrolling interest in property partnerships	14,850	14,340	46,484	33,967
Interest expense	95,366	92,032	277,790	282,709
Depreciation and amortization expense	157,996	152,164	480,210	463,288
Transaction costs	914	239	1,409	572
Payroll and related costs from management services contracts	2,516	0	7,371	0
General and administrative expense	29,677	25,792	94,039	84,319
Gains from early extinguishments of debt	0	0	0	14,354
Gains from investments in securities	1,075	944	1,454	2,716
Interest and other income	2,822	1,329	7,049	3,447
Gains on sales of real estate	7,863	2,891	122,552	6,791
Income (loss) from unconsolidated joint ventures	(4,313)	843	(3,083)	7,035
Direct reimbursements of payroll and related costs from management services contracts	2,516	0	7,371	0
Development and management services income	15,253	10,811	32,963	24,648
Net Operating Income	411,698	401,113	1,219,835	1,202,175
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	136,201	132,693	483,069	395,199
Preferred Stock Dividends / Distributions	(2,625)	(2,625)	(7,875)	(7,875)
Noncontrolling interest in property partnerships	(14,850)	(14,340)	(46,484)	(33,967)
Interest expense	(95,366)	(92,032)	(277,790)	(282,709)
Depreciation and amortization expense	(156,056)	(150,210)	(474,383)	(457,102)
Transaction costs	(914)	(239)	(1,409)	(572)
Payroll and related costs from management services contracts	(2,516)	0	(7,371)	0
General and administrative expense	(29,677)	(25,792)	(94,039)	(84,319)
Gains from early extinguishments of debt	0	0	0	(14,354)
Gains from investments in securities	(1,075)	(944)	(1,454)	(2,716)
Interest and other income	(2,822)	(1,329)	(7,049)	(3,447)
Income (loss) from unconsolidated joint ventures	4,313	(843)	3,083	(7,035)
Direct reimbursements of payroll and related costs from management services contracts	(2,516)	0	(7,371)	0
Development and management services income	(15,253)	(10,811)	(32,963)	(24,648)
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	136,201	132,693	483,069	395,199
Preferred Stock Dividends / Distributions	2,625	2,625	7,875	7,875
Noncontrolling interest in property partnerships	14,850	14,340	46,484	33,967
Interest expense	95,366	92,032	277,790	282,709
Depreciation and amortization expense	156,056	150,210	474,383	457,102
Transaction costs	914	239	1,409	572
Payroll and related costs from management services contracts	2,516	0	7,371	0
General and administrative expense	29,677	25,792	94,039	84,319
Gains from early extinguishments of debt	0	0	0	14,354
Gains from investments in securities	1,075	944	1,454	2,716
Interest and other income	2,822	1,329	7,049	3,447
Gains on sales of real estate	9,154	2,891	126,831	7,368
Income (loss) from unconsolidated joint ventures	(4,313)	843	(3,083)	7,035
Direct reimbursements of payroll and related costs from management services contracts	2,516	0	7,371	0
Development and management services income	15,253	10,811	32,963	24,648
Net Operating Income	$ 411,698	$ 401,113	$ 1,219,835	$ 1,202,175