Stock-Based Compensation - Details of Nonvested Restricted Stock Units Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant-date fair value of shares vested	$ 1,611	$ 1,073	$ 1,821
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning Balance (in shares)	230,962
Granted (in shares)	158,256
Vested (in shares)	(88,672)
Canceled (in shares)	(49,720)
Accrued dividend equivalents (in shares)	4,376
Ending Balance (in shares)	255,202	230,962
Vested but not released (in shares)	1,508	1,483
Outstanding (in shares)	256,710
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning Balance (in dollars per share)	$ 33.49
Granted (in dollars per share)	28.58	$ 32.52	$ 34.53
Vested (in dollars per share)	35.04
Canceled (in dollars per share)	30.02
Accrued dividend equivalents (in dollars per share)	30.62
Ending Balance (in dollars per share)	30.86	33.49
Vested but not released (in dollars per share)	18.04
Outstanding (in dollars per share)	$ 30.78
Aggregate intrinsic value of shares outstanding	$ 7,902
Weighted-average remaining contractual term of shares outstanding	20 months
Granted (in dollars per share)	$ 28.58	$ 32.52	$ 34.53
Weighted average grant-date fair value of shares vested	$ 3,107	$ 3,336	$ 3,000