Commitments and Contingencies (Textual) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Future obligations under leases	$ 135.7
Outstanding letters of credit and performance bonds	3.8
Lease operating expenses	$ 2.4	$ 2.0	$ 1.3
Other Commitments [Line Items]
Weighted average remaining term (in years)	3 years
Ground Leases
Other Commitments [Line Items]
Weighted average remaining term (in years)	78 years
Ground and Operating Lease Commitments
Other Commitments [Line Items]
Future lease commitments	$ 211.2