Accounts Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accounts Receivable Additional Disclosures [Abstract]
Accounts Receivable, Net, Current	$ 13,934	$ 10,522
Unbilled accounts receivable	600,446	490,533
Other Receivables	8,384	12,251
Accounts receivable, net	622,764	513,306
Allowance for Doubtful Accounts Receivable, Current	1,000	1,000
Unbilled accounts receivable [Abstract]
Accrued worksite employee payroll cost	513,397	409,653
Unbilled revenues	123,849	100,934
Client Prepayments Included in Cash Balance	(36,800)	(20,054)
Unbilled accounts receivable	$ 600,446	$ 490,533