Other Assets and Accrued Liabilities - Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Prepaid rent	$ 9,687		$ 10,519
Prepaid maintenance expenses	4,282		3,062
Derivative Asset, Current	3,673		2,411
Deferred contract and other costs	46,558		1,119
Prepaid expenses and other	$ 64,200	$ 53,688	$ 17,111