Real Estate Activity During the Nine Months Ended September 30, 2013 (Summary Of The Discontinued Operations Related to Montvale Center, 303 Almaden Blvd, 1301 New York Avenue and Beford Business Park) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		0 Months Ended	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Aug. 22, 2013 1301 New York Avenue [Member]	Sep. 30, 2013 1301 New York Avenue [Member]	Mar. 31, 2013 303 Almaden blvd [Member]	Sep. 30, 2012 Montvale Center, 303 Almaden Blvd and Bedford Business Park [Member]	Sep. 30, 2013 Montvale Center, 303 Almaden Blvd and Bedford Business Park [Member]	Sep. 30, 2012 Montvale Center, 303 Almaden Blvd, 1301 New York Avenue and Bedford Business Park [Member] [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenue	$ 574,082	$ 466,680	$ 1,566,834	$ 1,376,448		$ 1,511		$ 4,882	$ 10,469	$ 17,940
Expenses
Operating						433		1,781	3,447	6,725
Depreciation and amortization	152,156	108,609	402,892	323,680		0		901	1,065	3,675
Total expenses	384,693	303,945	1,071,881	895,990		433		2,682	4,512	10,400
Operating income	189,389	162,735	494,953	480,458		1,078		2,200	5,957	7,540
Other expense
Interest expense	(122,173)	(105,030)	(325,746)	(308,168)		0		(650)	(360)	(1,944)
Income from discontinued operations	89,643	1,550	112,046	44,041		1,078		1,550	5,597	5,596
Gains on sale of real estate from discontinued operations	88,565	0	88,565	38,445	88,600	88,565		0	88,565	38,445
Gain on forgiveness of debt from discontinued operations attributable to Boston Properties LImited Partnership	0	0	20,736	0		0		0		0
Impairment loss from discontinued operations attributable to Boston Properties Limited Partnership	$ 0	$ 0	$ (2,852)	$ 0		$ 0	$ (2,900)	$ 0		$ 0