Real Estate Joint Ventures - Summarized Financial Information for Unconsolidated Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Investment In Unconsolidated Affiliates [Line Items]
Cash and cash equivalents	$ 201,325	$ 212,773	$ 289,708	$ 34,515
Other assets	33,540	36,573
Total assets	978,985	982,742
Equity	659,054	665,263
Total liabilities and equity	978,985	982,742
Other affiliates
Investment In Unconsolidated Affiliates [Line Items]
Cash and cash equivalents	13,164	13,760
Other assets	59	58
Total assets	13,223	13,818
Accounts payable and other liabilities	1,381	1,978
Equity	11,842	11,840
Total liabilities and equity	$ 13,223	$ 13,818