Goodwill - Summary of the Gross Amount and Accumulated Impairment Losses of Goodwill (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill, gross amount	$ 176,157	$ 176,157	$ 176,157
Accumulated impairment losses	(151,117)	(151,117)	(151,117)
Goodwill, carrying value	25,040	25,040	25,040
Tech
Goodwill [Line Items]
Goodwill, gross amount	156,391	156,391	156,391
Accumulated impairment losses	(139,357)	(139,357)	(139,357)
Goodwill, carrying value	17,034	17,034	17,034
FA
Goodwill [Line Items]
Goodwill, gross amount	19,766	19,766	19,766
Accumulated impairment losses	(11,760)	(11,760)	(11,760)
Goodwill, carrying value	$ 8,006	$ 8,006	$ 8,006