Debt - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Components of interest expense
Contractual coupon interest	$ 36,879	$ 2,121	$ 72,926	$ 4,047
Non-cash interest expense (including amortization of discounts and deferred financing costs)	9,996	298	19,962	588
Total interest expense	$ 46,875	$ 2,419	$ 92,888	$ 4,635