Property and Equipment - Schedule of Cost Basis and Estimated Useful Lives of Property and Equipment (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Computer hardware and software	[1]	$ 45,482	$ 40,587
Leasehold improvements	[1]	60,520	56,095
Furniture, fixtures and equipment	[1]	23,633	23,071
Building and improvements	[1]	9,163	8,485
Library materials	[1]	24	24
Vehicles	[1]	55	56
Construction in progress	[1]	3,189	823
Property plant and equipment, Total	[1]	142,066	129,141
Less-accumulated depreciation	[1]	(113,711)	(101,380)
Total property and equipment, net	[1]	$ 28,355	$ 27,761
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life (in years)	[1]	Shorter of Life of Lease or Useful Life
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life (in years)	[1]	3 years
Furniture, Fixtures and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life (in years)	[1]	5 years
Furniture, Fixtures and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life (in years)	[1]	10 years
Building and Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life (in years)		15 years
Building and Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life (in years)		35 years
Library Materials [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life (in years)	[1]	10 years
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life (in years)	[1]	5 years

[1] Property and equipment which were fully depreciated and no longer in use by the Company were retired during the years ended December 31, 2021 and 2020; therefore, both the cost of the asset and the related accumulated depreciation balances were reduced to zero for these assets.