Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Accounting Policies [Abstract]

Fair Value, by Balance Sheet Grouping [Table Text Block]

	December 31, 2012					December 31, 2011
	Carrying Amount			Estimated Fair Value		Carrying Amount			Estimated Fair Value
Mortgage notes payable	$	3,102,485		$	3,256,940	$	3,123,267		$	3,297,903
Unsecured senior notes	4,639,528			5,162,486		3,865,186			4,148,461
Unsecured exchangeable senior notes	1,170,356		(1)	1,278,554		1,715,685		(1)	1,904,115
Total	$	8,912,369		$	9,697,980	$	8,704,138		$	9,350,479

 _______________

(1) Includes the net impact of Accounting Standards Codification (“ASC”) ASC 470-20 totaling approximately $25.5 million and $54.5 million at December 31, 2012 and December 31, 2011, respectively.

Gaap Reconciliation Of Net Income To Taxable Income, Table [Table Text Block]

The following table reconciles GAAP net income attributable to Boston Properties, Inc. to taxable income:

	For the year ended December 31,
	2012			2011			2010
	(in thousands)
Net income attributable to Boston Properties, Inc.	$	289,650		$	272,679		$	159,072
Straight-line rent adjustments	(80,281		)	(77,422		)	(75,943		)
Book/Tax differences from depreciation and amortization	105,599			117,675			67,362
Book/Tax differences on gains/losses from capital transactions	(22,408		)	(38,443		)	(2,373		)
Book/Tax differences from stock-based compensation	19,660			827			(1,957		)
Book/Tax differences on losses from early extinguishments of debt	—			40			6,448
Other book/tax differences, net	35,461			29,349			3,921
Taxable income	$	347,681		$	304,705		$	156,530

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

The following table summarizes the scheduled amortization of the Company's acquired “above-” and “below-market” lease intangibles for each of the five succeeding years (in thousands).

	Acquired Above-Market Lease Intangibles		Acquired Below-Market Lease Intangibles
2013	$	5,179	$	20,190
2014	4,220		19,095
2015	3,295		13,633
2016	2,550		11,823
2017	2,036		9,107

The following table summarizes the scheduled amortization of the Company's acquired in-place lease intangibles for each of the five succeeding years (in thousands).

	Acquired In-Place Lease Intangibles
2013	$	43,077
2014	35,861
2015	20,242
2016	15,041
2017	11,215

Schedule Of Future Contractual Minimum Lease Payments Under Non-Cancelable Ground Leases [Table Text Block]

Years Ending December 31,	(in thousands)
2013	$	12,820
2014	13,184
2015	13,507
2016	13,732
2017	13,963
Thereafter	913,655

Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes, Table [Table Text Block]

The tax treatment of common dividends per share for federal income tax purposes is as follows:

	For the year ended December 31,
	2012				2011						2010
	Per Share		%		Per Share			%			Per Share			%
Ordinary income	$	2.29	96.45	%	$	2.06	0.5839	97.39	%	0.9093	$	1.17	0.9093	58.39	%
Capital gain income	0.08		3.55	%	0.05		—	2.61	%	—	—		—	—	%
Return of capital	—		—	%	—		0.4161	—	%	0.0907	0.83		0.0907	41.61	%
Total	$	2.37	100.00	%	$	2.11		100.00	%		$	2.00	1	100.00	%

Property, Plant and Equipment [Table Text Block]

Depreciation is computed on a straight-line basis over the estimated useful lives of the assets as follows:

Land improvements	25 to 40 years
Buildings and improvements	10 to 40 years
Tenant improvements	Shorter of useful life or terms of related lease
Furniture, fixtures, and equipment	3 to 7 years