Basis of Presentation of Interim Period Statements - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2021 USD ($) Company	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Revenue recognition professional employer service contracts term	1 year
Professional employer service contract cancellation and termination period	30 days
Payment term for staffing customers	30 days
Number of wholly-owned insurance companies | Company	2
Cash and cash equivalents, maturity term	3 months
Allowance for doubtful accounts	$ 761,000		$ 757,000
Estimate of liability for unpaid safety incentives	6,900,000		$ 18,800,000
Income taxes paid	$ 210,000	$ 0