Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	$ 572,347	$ 451,939	$ 502,285
Preferred dividends / distributions	(10,500)	(10,500)	(10,500)
Noncontrolling interest-common units of the Operating Partnership	(66,807)	(52,210)	(59,260)
Noncontrolling interest in property partnerships	(62,909)	(47,832)	2,068
Losses from interest rate contracts	0	0	(140)
Interest expense	(378,168)	(374,481)	(412,849)
Impairment losses	(11,812)	0	(1,783)
Depreciation and amortization expense	(645,649)	(617,547)	(694,403)
Transaction costs	(1,604)	(668)	(2,387)
Payroll and related costs from management services contracts	(9,590)	0	0
General and administrative expense	(121,722)	(113,715)	(105,229)
Gains (losses) from early extinguishments of debt	16,490	(496)	371
Gains (losses) from investments in securities	1,865	(3,678)	(2,273)
Interest and other income	(10,823)	(5,783)	(7,230)
Gain on sale of investment in unconsolidated joint venture	0	0	(59,370)
Income from unconsolidated joint ventures	(2,222)	(11,232)	(8,074)
Direct reimbursements of payroll and related costs from management services contracts	(9,590)	0	0
Development and management services revenue	(45,158)	(34,605)	(28,284)
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	572,347	451,939	502,285
Preferred dividends / distributions	10,500	10,500	10,500
Noncontrolling interest-common units of the Operating Partnership	66,807	52,210	59,260
Noncontrolling interest in property partnerships	62,909	47,832	(2,068)
Losses from interest rate contracts	0	0	140
Interest expense	378,168	374,481	412,849
Impairment losses	11,812	0	1,783
Depreciation and amortization expense	645,649	617,547	694,403
Transaction costs	1,604	668	2,387
Payroll and related costs from management services contracts	9,590	0	0
General and administrative expense	121,722	113,715	105,229
Gains (losses) from early extinguishments of debt	(16,490)	496	(371)
Gains (losses) from investments in securities	(1,865)	3,678	2,273
Interest and other income	10,823	5,783	7,230
Gains on sales of real estate	182,356	7,663	80,606
Gain on sale of investment in unconsolidated joint venture	0	0	59,370
Income from unconsolidated joint ventures	2,222	11,232	8,074
Direct reimbursements of payroll and related costs from management services contracts	9,590	0	0
Development and management services revenue	45,158	34,605	28,284
Net Operating Income	1,649,314	1,605,435	1,601,302
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	656,903	512,866	575,341
Preferred dividends / distributions	(10,500)	(10,500)	(10,500)
Noncontrolling interest in property partnerships	(62,909)	(47,832)	2,068
Losses from interest rate contracts	0	0	(140)
Interest expense	(378,168)	(374,481)	(412,849)
Impairment losses	(10,181)	0	(1,783)
Depreciation and amortization expense	(637,891)	(609,407)
Transaction costs	(1,604)	(668)	(2,387)
Payroll and related costs from management services contracts	(9,590)	0	0
General and administrative expense	(121,722)	(113,715)	(105,229)
Gains (losses) from early extinguishments of debt	16,490	(496)	371
Gains (losses) from investments in securities	1,865	(3,678)	(2,273)
Interest and other income	(10,823)	(5,783)	(7,230)
Gain on sale of investment in unconsolidated joint venture	0	0	(59,370)
Income from unconsolidated joint ventures	(2,222)	(11,232)	(8,074)
Direct reimbursements of payroll and related costs from management services contracts	(9,590)	0	0
Development and management services revenue	(45,158)	(34,605)	(28,284)
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	656,903	512,866	575,341
Preferred dividends / distributions	10,500	10,500	10,500
Noncontrolling interest in property partnerships	62,909	47,832	(2,068)
Losses from interest rate contracts	0	0	140
Interest expense	378,168	374,481	412,849
Impairment losses	10,181	0	1,783
Depreciation and amortization expense	637,891	609,407	682,776
Transaction costs	1,604	668	2,387
Payroll and related costs from management services contracts	9,590	0	0
General and administrative expense	121,722	113,715	105,229
Gains (losses) from early extinguishments of debt	(16,490)	496	(371)
Gains (losses) from investments in securities	(1,865)	3,678	2,273
Interest and other income	10,823	5,783	7,230
Gains on sales of real estate	190,716	8,240	82,775
Gain on sale of investment in unconsolidated joint venture	0	0	59,370
Income from unconsolidated joint ventures	2,222	11,232	8,074
Direct reimbursements of payroll and related costs from management services contracts	9,590	0	0
Development and management services revenue	45,158	34,605	28,284
Net Operating Income	$ 1,649,314	$ 1,605,435	$ 1,601,302