The percentage of loan attributable to amortization per year.

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Debt Instrument, Forgiveness Ineligibility, Interest Rate Stated Percentage

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Debt Instrument, Forgiveness Ineligibility, Payment Deferral Period

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Minimum reference rate for the variable rate of the debt instrument.

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Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included In Earnings, Mark-To-market Adjustment

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Loan Restructuring, Modifications, Amount

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Amount of amortization expense attributable to debt issuance costs.

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

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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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Face (par) amount of debt instrument at time of issuance.

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

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Gross amount of debt extinguished.

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The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

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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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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, 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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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

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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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Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

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Debt - Narrative (Details)			1 Months Ended	3 Months Ended		9 Months Ended
Debt - Narrative (Details)	Jul. 27, 2020 USD ($)	Jul. 31, 2015 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jul. 31, 2020 EUR (€)	May 31, 2020 EUR (€)	Mar. 23, 2020 EUR (€)	Dec. 31, 2019 USD ($)	Jan. 31, 2019 USD ($)
Credit facility
Interest rate				7.25%		7.25%
Long term debt, gross				$ 277,184,000		$ 277,184,000
Amortization of deferred financing costs						$ 2,342,000	$ 2,032,000
Payment Protection Program, CARES Act
Credit facility
Forgiveness ineligibility, interest rate				100.00%		100.00%
Forgiveness ineligibility, payment deferral period						6 months
Interest rate swap
Credit facility
Cash flow hedge, gain (loss)			$ 4,000,000.0
Interest rate swap \| Derivative financial instruments, liabilities
Credit facility
Mark-to-market adjustment				$ (300,000)		$ 400,000
Minimum
Credit facility
Commitment fee percentage	0.375%
Minimum \| Payment Protection Program, CARES Act
Credit facility
Debt instrument, term						2 years
Maximum
Credit facility
Commitment fee percentage	0.50%
Maximum \| Payment Protection Program, CARES Act
Credit facility
Debt instrument, term						5 years
Eurodollar
Credit facility
Margin of interest (as a percent)	6.25%
Eurodollar \| Minimum
Credit facility
Margin of interest (as a percent)	6.00%
Eurodollar \| Maximum
Credit facility
Margin of interest (as a percent)	6.25%
Base Rate
Credit facility
Margin of interest (as a percent)	5.25%
Term loan
Credit facility
Face amount	$ 275,000,000.0	$ 425,000,000.0		275,000,000.0		$ 275,000,000.0		€ 600,000	€ 300,000	€ 1,000,000.0
Interest rate								2.50%	2.20%	1.50%
Extinguishment of debt	107,100,000
Loan balance	403,800,000			275,000,000		275,000,000					$ 405,875,000
Modification of debt	296,700,000
Write off of deferred debt issuance cost	700,000
Unamortized issuance costs	1,900,000
Long term debt, gross				0		0
Debt issuance costs incurred	7,500,000	$ 12,900,000
Amortization of deferred financing costs				200,000	$ 600,000	1,400,000	$ 1,700,000
Deferred issuance costs, net				9,018,000		9,018,000					$ 3,886,000
Fair value of debt				267,400,000		267,400,000
Amortization per year (as a percent)		1.00%
Term loan \| Restated Credit Facility
Credit facility
Debt issuance costs incurred	6,400,000
Amortization of deferred financing costs				300,000
Term loan \| Existing Lenders
Credit facility
Write off of deferred debt issuance cost	4,400,000
Term loan \| New Lenders
Credit facility
Debt issuance costs incurred	1,100,000
Revolving loan
Credit facility
Maximum borrowing available	25,000,000.0
Long term debt, gross				$ 0		$ 0
Debt issuance costs incurred	500,000	$ 1,300,000
Letter-of-credit sub-facility
Credit facility
Maximum borrowing available	10,000,000.0											$ 10,000,000.0
Credit Facility \| Alternate base rate
Credit facility
Margin of interest (as a percent)		3.75%
Credit Facility \| LIBOR
Credit facility
Margin of interest (as a percent)		4.75%
Variable rate base minimum (as a percent)		1.00%
Bridge Loan
Credit facility
Maximum borrowing available	$ 5,000,000.0