Earnings Per Share / Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic Earnings:
Net income attributable to the Company's shareholders/unitholders (Numerator)									$ 572,347	$ 451,939	$ 502,285
Net income attributable to the Company in Shares / Units (Denominator)									154,427,000	154,190,000	153,715,000
Earnings Per Share, Basic	$ 0.96	$ 0.77	$ 0.83	$ 1.14	$ 0.67	$ 0.76	$ 0.87	$ 0.63	$ 3.71	$ 2.93	$ 3.27
Net income attributable to the Company's shareholders/unitholders (in dollars per share / unit)									$ 3.71	$ 2.93	$ 3.27
Allocation of undistributed earnings to participating securities (Numerator)									$ (101)		$ (283)
Allocation of undistributed earnings to participating securities (in shares) (Denominator)									0		0
Allocation of undistributed earnings to participating securities (in dollars per share / unit)									$ 0.00		$ 0
Net Income Available To Common Stockholders After Allocation of Undistributed Earnings to Participating Securities Basic									$ 572,246		$ 502,002
Weighted Average Number Of Shares Outstanding After Allocation of Undistributed Earnings to Participating Securities Basic (in shares)									154,427,000		153,715,000
Earnings Per Share After Allccation of Undistributed Earnings to Particiapting Securities Basic (dollars per share)									$ 3.71		$ 3.27
Effect of Dilutive Securities:
Stock Based Compensation (Numerator)									$ 0	$ 0	$ 0
Stock Based Compensation, Shares / Units (Denominator)									255,000	200,000	262,000
Stock Based Compensation Per Share / Unit Amount									$ (0.01)	$ 0.00	$ (0.01)
Diluted Earnings:
Diluted Earnings: Net income attributable to the Company's shareholders/unitholdersIncome (Numerator)									$ 572,246	$ 451,939	$ 502,002
Diluted Earnings Net income attributable to the Company's shareholders/unitholders Shares / Units (Denominator)									154,682,000	154,390,000	153,977,000
Diluted Earnings: Net income, Per Share / Unit Amount (in dollars per share / unit)	0.96	0.77	0.83	1.14	0.67	0.76	0.87	0.63	$ 3.70	$ 2.93	$ 3.26
Boston Properties Limited Partnership
Redeemable Common Units									17,485,000	17,471,000	17,646,000
Basic Earnings:
Net income attributable to the Company's shareholders/unitholders (Numerator)									$ 656,903	$ 512,866	$ 575,341
Net income attributable to the Company in Shares / Units (Denominator)									171,912,000	171,661,000	171,361,000
Earnings Per Share, Basic	1.01	0.79	0.85	1.17	0.69	0.77	0.88	0.64	$ 3.82	$ 2.99	$ 3.36
Net income attributable to the Company's shareholders/unitholders (in dollars per share / unit)											$ 3.36
Allocation of undistributed earnings to participating securities (Numerator)									$ (113)		$ (316)
Allocation of undistributed earnings to participating securities (in shares) (Denominator)									0		0
Allocation of undistributed earnings to participating securities (in dollars per share / unit)									$ 0		$ 0
Net Income Available To Common Stockholders After Allocation of Undistributed Earnings to Participating Securities Basic									$ 656,790		$ 575,025
Weighted Average Number Of Shares Outstanding After Allocation of Undistributed Earnings to Participating Securities Basic (in shares)									171,912,000		171,361,000
Earnings Per Share After Allccation of Undistributed Earnings to Particiapting Securities Basic (dollars per share)									$ 3.82		$ 3.36
Effect of Dilutive Securities:
Stock Based Compensation (Numerator)									$ 0	$ 0	$ 0
Stock Based Compensation, Shares / Units (Denominator)									255,000	200,000	262,000
Stock Based Compensation Per Share / Unit Amount									$ (0.01)	$ (0.01)	$ (0.01)
Diluted Earnings:
Diluted Earnings: Net income attributable to the Company's shareholders/unitholdersIncome (Numerator)									$ 656,790	$ 512,866	$ 575,025
Diluted Earnings Net income attributable to the Company's shareholders/unitholders Shares / Units (Denominator)									172,167,000	171,861,000	171,623,000
Diluted Earnings: Net income, Per Share / Unit Amount (in dollars per share / unit)	$ 1.01	$ 0.79	$ 0.85	$ 1.17	$ 0.68	$ 0.77	$ 0.88	$ 0.64	$ 3.81	$ 2.98	$ 3.35