Debt - Debt Issuance Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Non-cash interest expense	$ 12,542	$ 14,100	$ 23,100
Deferred financing costs	513	81,097	$ 11,559
Unamortized balances of deferred financing costs	$ 88,241	$ 105,299