Debt (Debt Table) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Sep. 15, 2016
Debt Instrument [Line Items]
Outstanding borrowings	$ 494,000	$ 350,000
Unamortized debt issuance costs related to senior secured notes	(3,759)	(3,968)
Total debt	490,241	346,032
Less: Current portion of long-term debt	0	0
Long-term debt	490,241	346,032
Senior secured notes, due 2024 [Member]
Debt Instrument [Line Items]
Outstanding borrowings	350,000	350,000	$ 350,000
Revolving credit agreement [Member]
Debt Instrument [Line Items]
Outstanding borrowings	$ 144,000	$ 0

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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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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