Summary of Long-Term Debt (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Credit facility	$ 314,400	$ 362,400
Second Lien Facility	200,000	200,000
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	4,903	7,372
Debt Instrument, Unamortized Discount	(1,604)	(2,415)
Unamortized Debt Issuance Expense	(3,299)	(4,957)
Long-term Debt	514,400	562,400
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ 509,497	$ 555,028
Second Lien Facility
Debt Instrument [Line Items]
Credit facility interest rate option one, applicable margin rate over Adjusted LIBOR	7.25%
Second Lien Facility, Interest Rate	8.00%

Debt Instrument Interest Additional Interest Above LIBOR Rate

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- Definition

Second Lien Facility

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- Definition

Second Lien Facility, Interest Rate

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- Definition

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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- Definition

Amount, after accumulated amortization, of debt discount.

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- Definition

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

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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- Definition

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

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- Definition

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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Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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