Long-Term Debt and Interest Expense - Unamortized Discounts (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Unamortized deferred debt costs	$ 154	$ 166
Unamortized discounts and deferred debt costs	10,415	11,901
Capital Leases - Short-term
Debt Instrument [Line Items]
Unamortized discount	1,652	1,657
Capital Leases - Long-term
Debt Instrument [Line Items]
Unamortized discount	0	891
Term Loan
Debt Instrument [Line Items]
Unamortized discount	$ 8,609	$ 9,187

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

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Amount, after accumulated amortization, of debt discount (premium).

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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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