Long-Term Debt - Maturities Of Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Less than one year	$ 42,937
One to two years	38,333
Two to three years	8,749
Three to four years	9,186
Four to five years	209,644
Over five years	5,001
Gross debt	313,850
Unamortized debt issuance costs	(8,840)	$ (9,477)
Total debt	305,010	349,563
Less: current maturities	(42,873)	(90,651)
Long-term debt	262,137	258,912
Convertible Senior Notes Maturing May 2022
Debt Instrument [Line Items]
Less than one year	35,000
Gross debt	35,000	35,000
Unamortized debt issuance costs	(64)
Total debt	34,936
Less: current maturities	(34,936)
Convertible Senior Notes Maturing September 2023
Debt Instrument [Line Items]
One to two years	30,000
Gross debt	30,000	30,000
Unamortized debt issuance costs	(314)
Total debt	29,686
Long-term debt	29,686
Convertible Senior Notes Maturing February 2026
Debt Instrument [Line Items]
Four to five years	200,000
Gross debt	200,000	200,000
Unamortized debt issuance costs	(5,901)
Total debt	194,099
Long-term debt	194,099
MARAD Debt Maturing February 2027
Debt Instrument [Line Items]
Less than one year	7,937
One to two years	8,333
Two to three years	8,749
Three to four years	9,186
Four to five years	9,644
Over five years	5,001
Gross debt	48,850	$ 56,410
Unamortized debt issuance costs	(2,561)
Total debt	46,289
Less: current maturities	(7,937)
Long-term debt	$ 38,352

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 classified as noncurrent. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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