Real Estate Activity During The Three Months Ended March 31, 2012 (Summary Of The Discontinued Operations Related To Montvale Center) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue	$ 447,662	$ 417,214
Depreciation and amortization expense	109,673	109,237
Total expenses	303,001	279,321
Operating income	144,661	137,893
Interest expense	(103,237)	(98,525)
Noncontrolling interest in loss from discontinued operations - common units of the Operating Partnership	1,942	(61)
Loss from discontinued operations attributable to Boston Properties, Inc.	15,709	(436)
Gain on forgiveness of debt from discontinued operations	17,807
Montvale Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue	222	661
Operating expenses	92	341
Depreciation and amortization expense	64	191
Total expenses	156	532
Operating income	66	129
Interest expense	(222)	(626)
Loss from discontinued operations	(156)	(497)
Noncontrolling interest in loss from discontinued operations - common units of the Operating Partnership	17	61
Loss from discontinued operations attributable to Boston Properties, Inc.	(139)	(436)
Gain on forgiveness of debt from discontinued operations	17,807
Noncontrolling interest in gain on forgiveness of debt from discontinued operations - common units of the Operating Partnership	(1,959)
Gain on forgiveness of debt from discontinued operations attributable to Boston Properties, Inc	$ 15,848