Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2023 Segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021
Summary Of Significant Accounting Policies [Line Items]
Reserve for uncollectible accounts		$ 34.7	$ 38.6
Number of reportable segments | Segment	2
Number of Reporting Units | Segment	2
Accrual for estimated claims		39.1	$ 38.8
Federal and State [Member]
Summary Of Significant Accounting Policies [Line Items]
State and federal tax net operating losses, valuation allowance		$ 1.2
Software Development [Member]
Summary Of Significant Accounting Policies [Line Items]
Intangible assets estimated useful life		10 years
Leasehold Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]		us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember
Minimum [Member] | Investees [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage		50.00%
Maximum [Member] | Customer Concentration Risk [Member] | Revenue [Member] | Service [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk (as a percentage)		10.00%	10.00%	10.00%
Maximum [Member] | Building And Improvement [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated life		40 years
Maximum [Member] | Computer Equipment and Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated life		10 years
Maximum [Member] | Furniture and Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated life		10 years
Maximum [Member] | Transportation Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment estimated life		16 years