Long-Term Debt and Interest Expense - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Debt Disclosure [Abstract]
Cash payments for interest	$ 1,752	$ 8,578
Change in accrued interest	8,148	221
Amortization of discounts	262	1,474
Amortization of deferred debt costs	564	177
Commitment and other fees paid	11	809
Other	19	24
Interest expense	$ 10,756	$ 11,283