Commitments and Contingencies (Textual) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Outstanding commitments to fund real estate projects	$ 82,400
Outstanding Performance Bonds and Letters of Credit	1,900
Lease operating expenses	2,000	$ 1,300	$ 1,100
Future lease commitments	$ 144,900
Weighted average remaining terms of ground leases (in years)	85 years 7 months
Weighted average remaining terms of operating leases (in years)	2 years 2 months