U.K. Sale - Result of Operation (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of taxes	$ 674	$ (12,641)	$ 29,804
Discontinued Operations [Member] \| U.K. Sales [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue	285,343	62,520	817,772
Salaries, wages and benefits	159,840	35,937	465,514
Professional fees	31,987	6,815	92,264
Supplies	9,434	2,217	28,274
Rents and leases	11,817	2,509	34,858
Other operating expenses	28,880	6,682	85,682
Depreciation and amortization	18,780		55,739
Interest expense, net	238	10	666
Loss on sale		14,254
Loss on impairment	20,239		20,239
Transaction-related expenses	5,479	6,265	7,735
Total expenses	286,694	74,689	790,971
(Loss) income from discontinued operations before income taxes	(1,351)	(12,169)	26,801
(Benefit from) provision for income taxes	(2,025)	472	(3,003)
Income (loss) from discontinued operations, net of taxes	$ 674	$ (12,641)	$ 29,804

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