Represents the total debt to EBITDA ratio that is required to be maintained by the entity under the credit agreement.

No definition available.

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Credit agreement debt to EBITDA ratio that is required to be maintained step down.

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No definition available.

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Represents the fixed charge coverage ratio that is required to be maintained by the entity under the credit agreement.

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No definition available.

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Represents the period of total debt to EBITDA ratio considered for calculation of interest rate of debt instrument under the credit agreement.

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No definition available.

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Debt Instrument, Floor Interest Rate

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No definition available.

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Represents the redemption price of debt instrument upon their stated maturity.

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No definition available.

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Element represents the debt instrument redemption amount.

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No definition available.

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Element represents the debt redemption amount.

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No definition available.

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Line Of Credit Facility, Fees And Other Closing Cost

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No definition available.

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Line of Credit Facility, Increase To Maximum Borrowing Capacity

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No definition available.

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Line Of Credit Facility, Liquidity Test Minimum

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No definition available.

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Line Of Credit Facility, Percentage Of Scheduled Quarterly Amortization Of Principal Installments

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No definition available.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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No definition available.

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- Definition

States whether the entity was in compliance with the debt covenants throughout the reporting period, and describes facts and circumstances of any compliance failure.

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Contractual interest rate for funds borrowed, under the debt agreement.

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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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No definition available.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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End date of debt instrument redemption period, in CCYY-MM-DD format.

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Cap rate on an interest rate derivative such as an interest rate cap or collar. If market rates exceed the cap rate, a payment or receipt is triggered on the contract.

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No definition available.

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Nominal or face amount used to calculate payment on derivative.

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Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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No definition available.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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No definition available.

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Date the credit facility terminates, in CCYY-MM-DD format.

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The effective interest rate at the end of the reporting period.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of long-term debt and lease obligation, including portion classified as current.

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No definition available.

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Borrowing Arrangements - Narrative (Details)		1 Months Ended	3 Months Ended		9 Months Ended	12 Months Ended
Borrowing Arrangements - Narrative (Details)	May 06, 2020 USD ($)	May 31, 2019 USD ($)	Jun. 30, 2021	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2019	Nov. 30, 2018 USD ($)
Debt Instrument [Line Items]
Debt instrument, covenant compliance					As of September 30, 2020, the Company was in compliance with its debt covenants under the Credit Agreement.
Long-term borrowings				$ 371,300,000	$ 371,300,000	$ 369,000,000.0
Redemptions of convertible debentures					0	0
Approximate redemption value of convertible debentures					$ 1,100,000	1,100,000
Interest Rate Collars
Debt Instrument [Line Items]
Interest rate collar, term		3 years
Notional amount		$ 222,300,000
Derivative, cap interest rate				2.50%	2.50%
Senior Credit Facility, Net of Discount
Debt Instrument [Line Items]
Maturity Date					Nov. 30, 2023
Long-term borrowings				$ 339,900,000	$ 339,900,000	$ 345,900,000
Weighted average interest rate				3.80%	3.80%			3.80%
Convertible Subordinated Debt
Debt Instrument [Line Items]
Redemption price upon stated maturity (in dollars per share) \| $ / shares					$ 19.18
Redemptions stated maturity date					Apr. 01, 2028
Amended Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity									$ 550,000,000.0
Percentage principal installments					1.25%
Amended Credit Agreement \| Forecast
Debt Instrument [Line Items]
Percentage principal installments			1.875%
Amended Credit Agreement \| Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 370,000,000.0								325,000,000.0
Increase to borrowing capacity	$ 45,000,000.0
Line of credit facility, expiration date	May 05, 2021
Liquidity test minimum							$ 50,000,000.0
Amended Credit Agreement \| Letter of Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity									100,000,000.0
Amended Credit Agreement \| Term Loan Facility
Debt Instrument [Line Items]
Maximum borrowing capacity									$ 225,000,000.0
Amended Credit Agreement \| Senior Credit Facility, Net of Discount
Debt Instrument [Line Items]
Fees and other closing cost	$ 1,700,000
Letters of credit outstanding				$ 52,000,000.0	$ 52,000,000.0
Long-term borrowings				$ 343,100,000	$ 343,100,000
Amended Credit Agreement \| Senior Credit Facility, Net of Discount \| Maximum
Debt Instrument [Line Items]
Total debt to EBITDA ratio that is required to be maintained				5.50	4.25
Credit agreement total debt to EBITDA ratio that is required to be maintained step down					4.00
Amended Credit Agreement \| Senior Credit Facility, Net of Discount \| Minimum
Debt Instrument [Line Items]
Fixed charge coverage ratio that is required to be maintained				2.75	3.50
Amended Credit Agreement \| Senior Credit Facility, Net of Discount \| Revolving Credit Facility
Debt Instrument [Line Items]
Interest rate	0.375%
Amended Credit Agreement \| Senior Credit Facility, Net of Discount \| LIBOR Loans
Debt Instrument [Line Items]
Period of total debt to EBITDA ratio					12 months
Amended Credit Agreement \| Senior Credit Facility, Net of Discount \| Base Rate Loans \| Federal Funds
Debt Instrument [Line Items]
Interest rate margin on variable rate basis					0.50%
Amended Credit Agreement \| Senior Credit Facility, Net of Discount \| Base Rate Loans \| LIBOR
Debt Instrument [Line Items]
Interest rate margin on variable rate basis	2.75%				1.00%
Floor interest rate	1.00%				0.00%
Senior Credit Facility \| Senior Credit Facility, Net of Discount
Debt Instrument [Line Items]
Weighted average interest rate				3.60%	3.60%			3.50%