Noncontrolling Interest (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) property	Sep. 30, 2019 USD ($)
Noncontrolling Interest [Line Items]
Net income attributable to noncontrolling interest	$ (1,100)	$ (1,444)	$ (3,838)	$ (4,279)
Cash distribution for joint venture partners	5,324	$ 5,107	16,707	$ 16,294
Variable interest entity, consolidated, carrying amount, real estate assets	710,001		710,001
Variable interest entity, consolidated, carrying amount, mortgage debt	$ 620,000		$ 620,000
Joint Venture
Noncontrolling Interest [Line Items]
Ownership percentage by noncontrolling owners	45.00%		45.00%
Ownership percentage	55.00%		55.00%
Boston, MA \| Life Science Building \| Joint Venture
Noncontrolling Interest [Line Items]
Number of properties included in joint venture agreement \| property			1

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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