Debt - Schedule of Long-Term Debt (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020	Aug. 31, 2020
Debt Instrument [Line Items]
Long-term debt, gross	$ 268,384,000	$ 294,695,000
Unamortized debt discount	(27,132,000)	(30,248,000)
Debt issuance cost	(6,660,000)	(7,318,000)
Less: current maturities	(1,054,000)	(1,322,000)
Long-term debt, net of current portion	267,330,000	293,373,000
2025 Notes
Debt Instrument [Line Items]
Long-term debt, gross	300,341,000	316,863,000	$ 282,600,000
Unamortized debt discount			$ (32,900,000)
Other debt
Debt Instrument [Line Items]
Long-term debt, gross	1,835,000	2,272,000
2017 Credit Facility \| Credit Facility
Debt Instrument [Line Items]
Long-term debt, gross	$ 0	$ 13,126,000

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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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