Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Operating Income	$ 204,926	$ 201,273	$ 411,135	$ 378,170
Development and management services income	4,862	6,506	10,190	11,722
Income from unconsolidated joint ventures	3,078	2,834	17,912	5,650
Interest and other income	1,293	2,109	2,700	3,420
Gains (losses) from investments in securities	(24)	662	369	948
General and administrative expense	22,284	23,271	51,075	53,176
Transaction costs	208	661	535	1,098
Depreciation and amortization expense	167,844	154,628	322,067	308,898
Interest expense	108,534	110,977	217,291	224,531
Noncontrolling interest in property partnerships	9,264	7,553	24,472	11,907
Noncontrolling interest-redeemable preferred units of the Operating Partnership	3	320	6	939
Noncontrolling interest-common units of the Operating Partnership	9,394	8,883	29,530	15,010
Preferred dividends	2,618	2,618	5,207	5,207
Net income attributable to Boston Properties, Inc. common shareholders	79,460	76,527	250,694	130,594
Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Operating Income	390,400	373,327	774,622	729,620
Development and management services income	4,862	6,506	10,190	11,722
Income from unconsolidated joint ventures	3,078	2,834	17,912	5,650
Interest and other income	1,293	2,109	2,700	3,420
Gains (losses) from investments in securities	(24)	662	369	948
Gain on sales of real estate	0	0	95,084	0
General and administrative expense	22,284	23,271	51,075	53,176
Transaction costs	208	661	535	1,098
Depreciation and amortization expense	167,844	154,628	322,067	308,898
Interest expense	108,534	110,977	217,291	224,531
Noncontrolling interest in property partnerships	9,264	7,553	24,472	11,907
Noncontrolling interest-redeemable preferred units of the Operating Partnership	3	320	6	939
Noncontrolling interest-common units of the Operating Partnership	9,394	8,883	29,530	15,010
Preferred dividends	2,618	2,618	5,207	5,207
Net income attributable to Boston Properties, Inc. common shareholders	$ 79,460	$ 76,527	$ 250,694	$ 130,594