Subsequent Events (Details) $ in Thousands								12 Months Ended
	Apr. 01, 2019 USD ($)	Feb. 14, 2019 ft² yr	Feb. 09, 2019 USD ($) shares	Feb. 05, 2019 USD ($) shares	Jan. 24, 2019 USD ($) ft² a yr	Nov. 29, 2018 ft² a yr	Nov. 16, 2018 USD ($) ft² yr	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($)	Feb. 01, 2019 shares	Jan. 10, 2019 USD ($) ft²	Dec. 01, 2018 ft²	May 23, 2018 shares
Subsequent Event [Line Items]
Payments to Noncontrolling Interests								$ 82,501	$ 54,342	$ 55,474
Common stock, shares issued | shares								154,537,378	154,404,186					36,836
Subsequent Event [Member] | MYLTIPS 2019 [Member]
Subsequent Event [Line Items]
Value of MYLTIP Awards				$ 13,500
Subsequent Event [Member] | MYLTIPS 2019 [Member] | NAREIT Office Index adjusted [Member]
Subsequent Event [Line Items]
Target Tier | shares				110,367.00
Subsequent Event [Member] | MYLTIP 2016 [Member]
Subsequent Event [Line Items]
Value of MYLTIP Awards			$ 13,600
Final awards percentage of target			69.50%
MYLTIP Units forfeited | shares			364,980
Subsequent Event [Member] | Minimum [Member] | MYLTIPS 2019 [Member] | NAREIT Office Index adjusted [Member]
Subsequent Event [Line Items]
Minimum earned awards | shares				0
Subsequent Event [Member] | Maximum [Member] | MYLTIPS 2019 [Member] | NAREIT Office Index adjusted [Member]
Subsequent Event [Line Items]
maximum earned awards | shares				220,734
Subsequent Event [Member] | Restricted Stock [Member]
Subsequent Event [Line Items]
Common stock, shares issued | shares											23,083
Subsequent Event [Member] | LTIP Units [Member]
Subsequent Event [Line Items]
LTIP units issued (in shares) | shares				172,166
Boston Properties Limited Partnership
Subsequent Event [Line Items]
Payments to Noncontrolling Interests								$ 82,501	$ 54,342	$ 55,474
Salesforce Tower
Subsequent Event [Line Items]
Net Rentable Area | ft²													1,421,000
Salesforce Tower | Salesforce Tower | Subsequent Event [Member]
Subsequent Event [Line Items]
Ownership Percentage	5.00%
Payments to Noncontrolling Interests	$ 210,900
Repayment preferred equity	$ 24,100
Platform 16
Subsequent Event [Line Items]
Net Rentable Area | ft²						1,100,000
Ground Lease Term (in years) | yr						65
Area of Land | a						5.6
Platform 16 | Subsequent Event [Member]
Subsequent Event [Line Items]
Ground Lease Term (in years) | yr					65
Area of Land | a					5.6
325 Main Street | Subsequent Event [Member]
Subsequent Event [Line Items]
Net Rentable Area | ft²		115,000
Term of Lease Signed (in years) | yr		15
Square Footage Of Signed Lease | ft²		362,000
Future office building [Member] | 325 Main Street | Subsequent Event [Member]
Subsequent Event [Line Items]
Net Rentable Area | ft²		400,000
Future retail building [Member] | 325 Main Street | Subsequent Event [Member]
Subsequent Event [Line Items]
Net Rentable Area | ft²		38,000
2600 Tower Oaks Boulevard | Subsequent Event [Member]
Subsequent Event [Line Items]
Contractual Sales Price					$ 22,700
Net Rentable Area | ft²					179,000
Annapolis Junction Building Six [Member]
Subsequent Event [Line Items]
Net Rentable Area | ft²							119,000
Ownership Percentage							50.00%
Construction Loan							$ 13,100
Number of extensions							1
Extension Option (in years) | yr							1
Construction Loan Facility Borrowing Capacity							$ 14,300
Debt Instrument, Basis Spread on Variable Rate							2.00%
Annapolis Junction Building Six [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Net Rentable Area | ft²					119,000
Ownership Percentage					50.00%
Construction Loan					$ 13,000
Number of extensions					1
Extension Option (in years) | yr					1
Construction Loan Facility Borrowing Capacity					$ 14,300
Debt Instrument, Basis Spread on Variable Rate					2.00%
Carnegie Center | Subsequent Event [Member]
Subsequent Event [Line Items]
Aggregate purchase price												$ 42,900
Deferred purchase price												$ 8,600
Net Rentable Area | ft²												1,700,000.0