Long-Term Debt - Summary of Long-Term Debt (Details) - USD ($) $ in Thousands		Mar. 31, 2021	Dec. 31, 2020	Sep. 29, 2017
Debt Instrument [Line Items]
Revolving credit facility		$ 228,900	$ 314,400
Second Lien Facility		146,860	200,000	$ 200,000
Long-term Debt, Gross		375,760	514,400
Debt Instrument, Unamortized Discount		(1,096)	(1,604)	(4,000)
Unamortized Debt Issuance Expense		(3,602)	(3,299)	$ (8,200)
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net		371,062	509,497
Long-term Debt, Current Maturities		(7,500)	0
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	[1],[2]	4,698	4,903
Long-term Debt		$ 363,562	$ 509,497

[1] Discount and issuance costs of the Second Lien Facility are being amortized over the term of the underlying loan using the effective-interest method

[2] ssuance costs of the Credit Facility, which represent costs attributable to the access to credit over its contractual term, that have been presented as a component of Other assets (see Note 10) and are being amortized over the term of the Credit Facility using the straight-line method.