Long-Term Debt and Interest Expense - Unamortized Discounts (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Unamortized deferred debt issuance costs	$ 7,859	$ 7,959
Total unamortized discounts and deferred financing costs	10,807	11,169
Finance leases- short-term
Debt Instrument [Line Items]
Unamortized discount	359
Finance leases- short-term
Debt Instrument [Line Items]
Unamortized discount		479
10.75% Senior Notes due 2023
Debt Instrument [Line Items]
Unamortized discount	$ 2,589	$ 2,731

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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