Goodwill and Other Intangible Assets - Schedule of Reconciliation of Changes in Carrying Value of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill And Intangible Assets [Line Items]
Balance, Beginning of year	$ 118,312	$ 87,356
Business acquisitions	44,267	30,956
Balance, End of year	162,579	118,312
CTU [Member]
Goodwill And Intangible Assets [Line Items]
Balance, Beginning of year	45,938	45,938
Business acquisitions	27,790
Balance, End of year	73,728	45,938
AIUS [Member]
Goodwill And Intangible Assets [Line Items]
Balance, Beginning of year	72,374	41,418
Business acquisitions	16,477	30,956
Balance, End of year	$ 88,851	$ 72,374