Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Operating Income	$ 130,435	$ 143,567
Development and management services income	8,736	8,145
Income from unconsolidated joint ventures	8,721	11,721
Interest and other income	1,471	1,646
Gains from investments in securities	735	801
Gains from early extinguishments of debt	0	767
Income from discontinued operations	61	570
Gain on forgiveness of debt from discontinued operations	20,182	0
General and administrative expense	43,571	27,619
Transaction costs	443	2,104
Depreciation and amortization expense	120,595	108,462
Interest expense	100,433	103,237
Impairment loss	8,306	0
Impairment loss from discontinued operations	3,241	0
Noncontrolling interest in property partnerships	2,574	546
Noncontrolling interest-redeemable preferred units of the Operating Partnership	1,180	801
Noncontrolling interest-common units of the Operating Partnership	4,358	5,973
Noncontrolling interest in discontinued operations-common units of the Operating Partnership	1,819	61
Net income attributable to Boston Properties, Inc.	48,000	48,454
Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Operating Income	294,614	273,607
Development and management services income	8,736	8,145
Income from unconsolidated joint ventures	8,721	11,721
Interest and other income	1,471	1,646
Gains from investments in securities	735	801
Gains from early extinguishments of debt	0	767
Income from discontinued operations	61	570
Gain on forgiveness of debt from discontinued operations	20,182	0
General and administrative expense	43,571	27,619
Transaction costs	443	2,104
Depreciation and amortization expense	120,595	108,462
Interest expense	100,433	103,237
Impairment loss	8,306	0
Impairment loss from discontinued operations	3,241	0
Noncontrolling interest in property partnerships	2,574	546
Noncontrolling interest-redeemable preferred units of the Operating Partnership	1,180	801
Noncontrolling interest-common units of the Operating Partnership	4,358	5,973
Noncontrolling interest in discontinued operations-common units of the Operating Partnership	1,819	61
Net income attributable to Boston Properties, Inc.	$ 48,000	$ 48,454