Real Estate Activity During Nine Months Ended September 30, 2012 (Summary Of Discontinued Operations Related To Montvale Center And Bedford Business Park) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue	$ 470,904	$ 449,703	$ 1,389,028	$ 1,298,852
Expenses
Depreciation and amortization	111,360	108,674	331,943	327,526
Total expenses	308,082	285,873	908,476	844,066
Operating income	162,822	163,830	480,552	454,786
Other expense
Interest expense	(105,030)	(95,117)	(308,168)	(288,225)
Income (loss) from discontinued operations		20	884	(60)
Noncontrolling interest in income (loss) from discontinued operations-common units of the Operating Partnership		(2)	(6,092)	8
Income (loss) from discontinued operations attributable to Boston Properties, Inc.		18	49,476	(52)
Gain on sale of real estate from discontinued operations			36,877
Gain on forgiveness of debt from discontinued operations			17,807
Montvale Center and Bedford Business Park [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue		2,710	3,748	7,887
Expenses
Operating		1,209	1,602	3,531
Depreciation and amortization		821	1,040	2,477
Total expenses		2,030	2,642	6,008
Operating income		680	1,106	1,879
Other expense
Interest expense		(660)	(222)	(1,939)
Income (loss) from discontinued operations		20	884	(60)
Noncontrolling interest in income (loss) from discontinued operations-common units of the Operating Partnership		(2)	(93)	8
Income (loss) from discontinued operations attributable to Boston Properties, Inc.		18	791	(52)
Gain on sale of real estate from discontinued operations			36,877
Gain on forgiveness of debt from discontinued operations			17,807
Noncontrolling interest in gain on sale of real estate and gain on forgiveness of debt from discontinued operations-common units of the Operating Partnership			(5,999)
Gain on sale of real estate and gain on forgiveness of debt from discontinued operations attributable to Boston Properties, Inc.			$ 48,685