Real Estate Joint Ventures - Summarized Financial Information for Unconsolidated Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Investments in and Advances to Affiliates [Line Items]
Cash and cash equivalents	$ 216,982	$ 241,111	$ 201,325	$ 212,773
Other assets	36,473	38,410
Total assets	1,007,444	1,027,945
Equity	640,236	669,293
Total liabilities and equity	1,007,444	1,027,945
Other affiliates
Investments in and Advances to Affiliates [Line Items]
Cash and cash equivalents	11,412	11,948
Other assets	61	59
Total assets	11,473	12,007
Accounts payable and other liabilities	592	955
Equity	10,881	11,052
Total liabilities and equity	$ 11,473	$ 12,007