Real Estate Joint Ventures - Summarized Financial Information for Unconsolidated Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments in and Advances to Affiliates [Line Items]
Cash and cash equivalents	$ 241,111	$ 212,773	$ 34,515	$ 21,894
Other assets	38,410	36,853
Total assets	1,027,945	982,742
Equity	669,293	665,263
Total liabilities and equity	1,027,945	982,742
Other Affiliates
Investments in and Advances to Affiliates [Line Items]
Cash and cash equivalents	11,948	13,760
Other assets	59	58
Total assets	12,007	13,818
Accounts payable and other liabilities	955	1,978
Equity	11,052	11,840
Total liabilities and equity	$ 12,007	$ 13,818