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Forgivable loans, forgiveness period, maximum

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Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

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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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Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

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Description of Business and Summary of Significant Accounting Policies (Detail)	12 Months Ended
	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Aug. 20, 2018 USD ($)
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of reportable business segments \| segment	5
Advertising costs	$ 18,600,000	$ 15,500,000	$ 14,800,000
Provision for doubtful accounts	$ 19,602,000	$ 17,872,000	$ 15,386,000
Forgivable loans, forgiveness period, minimum	1 year
Forgivable loans, forgiveness period, maximum	10 years
Definite-lived intangible assets amortization period	13 years 4 months 24 days
Renewal term	7 years
Minimum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Definite-lived intangible assets amortization period	3 years
Renewal term	6 months
Maximum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Definite-lived intangible assets amortization period	15 years
Renewal term	7 years
Furniture, Equipment, And Internal-Use Software \| Minimum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful of furniture, equipment and internal use software (in years)	3 years
Furniture, Equipment, And Internal-Use Software \| Maximum
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful of furniture, equipment and internal use software (in years)	7 years
Software and Software Development Costs
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful of furniture, equipment and internal use software (in years)	3 years
Geographic Concentration Risk \| Consolidated Revenues \| Non U.S
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Revenue from the work of professionals	34.00%
Senior Notes \| Convertible Note Due 2023
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Interest rate (as a percent)				2.00%
Principal amount				$ 316,300,000