Supplementary Information - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 95,646	$ 89,601
Less: accumulated depreciation and amortization	56,036	53,269
Property and equipment, net	39,610	36,332
Land [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	9,993	10,067
Building and Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	15,640	15,630
Computer Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	43,760	41,451
Furniture Equipment and Other [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	13,664	10,136
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	9,961	9,652
Right-of-Use Assets Under Finance Leases [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 2,628	$ 2,665