Summary Of Significant Accounting Policies GAAP Reconciliation Of Net Income To Taxable Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Entity Information [Line Items]
Net income attributable to the Company	$ 103,829	$ 117,337	$ 133,709	$ 97,083	$ 147,214	$ 76,753	$ 96,597	$ 181,747	$ 462,439	$ 512,785	$ 583,106
Straight line rent and net above and below-market rent adjustments									(77,801)	(65,861)	(92,483)
Book/tax differences from depreciation and amortization									142,234	235,819	307,115
Book/Tax differences from interest expense									(18,136)	(36,223)	(43,349)
Book/tax differences on gains/(losses) from capital transactions									1,123	(70,880)	(74,482)
Book/tax differences from stock-based compensation									37,990	33,463	22,008
Tangible Property Regulations									(116,265)	(104,783)	(74,887)
Other book/tax differences, net									33,411	(6,121)	(15,259)
Taxable Income									464,995	498,199	611,769
Boston Properties Limited Partnership
Entity Information [Line Items]
Net income attributable to the Company	$ 117,667	$ 132,693	$ 151,844	$ 110,662	$ 166,801	$ 91,306	$ 109,938	$ 207,296	523,366	585,841	659,248
Straight line rent and net above and below-market rent adjustments									(86,773)	(73,604)	(103,227)
Book/tax differences from depreciation and amortization									144,436	245,239	329,629
Book/Tax differences from interest expense									(20,227)	(40,481)	(48,385)
Book/tax differences on gains/(losses) from capital transactions									784	(69,683)	(67,602)
Book/tax differences from stock-based compensation									42,371	37,397	24,565
Tangible Property Regulations									(129,673)	(117,102)	(83,587)
Other book/tax differences, net									37,607	(3,387)	(14,561)
Taxable Income									$ 511,891	$ 564,220	$ 696,080