Investments in Unconsolidated Joint Ventures (Acquisition, Development and Construction Arrangements/Sale of Joint Venture Interest or Property)(Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value	$ 170,516	$ 170,164
Mezzanine loan due July 2036
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value	24,965	24,542
Mezzanine loan due February 2022
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value	45,551	45,622
Participating Financing Due March 2018 [Member]
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value	$ 100,000	$ 100,000