Stock-Based Compensation - Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 6,053	$ 4,362	$ 3,868
Restricted stock units
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	3,729	2,836	3,196
Performance stock units
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 2,324	$ 1,526	$ 672