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Weighted average amortization period.

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The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		8 Months Ended	9 Months Ended	11 Months Ended
	Jan. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2021	Dec. 31, 2020
Summary Of Significant Accounting Policies [Line Items]
Depreciation and amortization	$ 2,105,000	$ 35,812,000	$ 36,756,000	$ 97,815,000	$ 106,493,000
Gain (loss) on foreign currency exchange rates	82,000			38,000	281,000
Goodwill [Member]
Summary Of Significant Accounting Policies [Line Items]
Goodwill impairment						$ 0
Other Comprehensive Income (Loss)
Summary Of Significant Accounting Policies [Line Items]
Gain (loss) on foreign currency exchange rates	0.0	(3,100,000)	7,000,000.0	(1,200,000)	(1,600,000)
Operations and Comprehensive Income (Loss)
Summary Of Significant Accounting Policies [Line Items]
Gain (loss) on foreign currency exchange rates	100,000	$ 200,000	$ 500,000	$ (400,000)	$ (100,000)
Customer Lists
Summary Of Significant Accounting Policies [Line Items]
Useful life		14 years	14 years	14 years	14 years	14 years
Depreciation and amortization	$ 800,000	$ 16,400,000	$ 17,800,000	$ 47,400,000	$ 49,100,000
Amortization Period	13 years 3 months 18 days
Customer Lists \| Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life	7 years
Customer Lists \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life	14 years
Trade Name [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of intangible assets					$ 0	$ 0
Useful life		20 years	20 years	20 years	20 years
Depreciation and amortization	$ 0	$ 2,000,000.0	$ 2,000,000.0	$ 5,400,000	$ 6,000,000.0
Trade Name [Member] \| Customer Lists
Summary Of Significant Accounting Policies [Line Items]
Impairment of intangible assets					$ 0	$ 0