Investment in Unconsolidated Real Estate Ventures - Summary of Financial Position of Real Estate Ventures (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Schedule Of Equity Method Investments [Line Items]
Company’s share of equity (Company’s basis)		$ 236,313	$ 281,331
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Net property		1,329,601	1,483,067
Other assets		205,631	231,972
Other liabilities		109,041	129,486
Debt, net		910,842	989,738
Equity		515,349	595,815
Company’s share of equity (Company’s basis)	[1]	$ 236,313	$ 281,331

[1] This amount includes the effect of the basis difference between the Company's historical cost basis and the basis recorded at the Real Estate Venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials occur from the impairment of investments, purchases of third party interests in existing Real Estate Ventures and upon the transfer of assets that were previously owned by the Company into a Real Estate Venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the Real Estate Venture level.