Earnings Per Share / Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Basic Earnings:
Net income attributable to the Company's common shareholders / unitholders	$ 98,105	$ 176,021
Net income attributable to the Company's common shareholders / unitholders (in shares / units)	154,525,000	154,385,000
Net income (in dollars per share / unit)	$ 0.63	$ 1.14
Allocation of undistributed earnings to participating securities (numerator)		$ (127)
Allocation of undistributed earnings to participating securities (in shares)		0
Allocation of undistributed earnings to participating securities (in dollars per shares / units)		$ 0
Net income attributable to the Company's common shareholders / unitholders		$ 175,894
Net income attributable to the Company's common shareholders / unitholders (in shares / units)		154,385,000
Net income attributable to the Company's common shareholders / unitholders (in dollars per share / unit)		$ 1.14
Effect of Dilutive Securities:
Stock Based Compensation, Income (Numerator)	$ 0	$ 0
Stock Based Compensation, Shares / Units (Denominator)	319,000	320,000
Stock Based Compensation, Per Share / Unit Amount (in dollars per share / unit)	$ 0.00	$ 0.00
Diluted Earnings:
Net income attributable to the Company's common shareholders / unitholders (Numerator)	$ 98,105	$ 175,894
Net income attributable to to the Company's shareholders / unitholder (number of shares)	154,844,000	154,705,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 0.63	$ 1.14
Boston Properties Limited Partnership
Entity Information [Line Items]
Redeemable Common Units	17,606,000	17,482,000
Basic Earnings:
Net income attributable to the Company's common shareholders / unitholders	$ 113,382	$ 200,907
Net income attributable to the Company's common shareholders / unitholders (in shares / units)	172,131,000	171,867,000
Net income (in dollars per share / unit)	$ 0.66	$ 1.17
Allocation of undistributed earnings to participating securities (numerator)		$ (141)
Allocation of undistributed earnings to participating securities (in shares)		0
Allocation of undistributed earnings to participating securities (in dollars per shares / units)		$ 0
Net income attributable to the Company's common shareholders / unitholders		$ 200,766
Net income attributable to the Company's common shareholders / unitholders (in shares / units)		171,867,000
Net income attributable to the Company's common shareholders / unitholders (in dollars per share / unit)		$ 1.17
Effect of Dilutive Securities:
Stock Based Compensation, Income (Numerator)	$ 0	$ 0
Stock Based Compensation, Shares / Units (Denominator)	319,000	320,000
Stock Based Compensation, Per Share / Unit Amount (in dollars per share / unit)	$ 0.00	$ 0.00
Diluted Earnings:
Net income attributable to the Company's common shareholders / unitholders (Numerator)	$ 113,382	$ 200,766
Net income attributable to to the Company's shareholders / unitholder (number of shares)	172,450,000	172,187,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 0.66	$ 1.17