Stockholders' Equity - Schedule of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Outstanding, Beginning Balance	436,000
Number of Shares, Granted	0	0	0
Number of Shares, Exercised	(90,000)
Number of Shares, Forfeited	(54,000)
Number of Shares, Outstanding, Ending Balance	292,000	436,000
Number of Shares, Vested and Exercisable at December 31, 2020	292,000
Weighted - Average Exercise Price Per Share, Outstanding, Beginning balance	$ 35.62
Weighted - Average Exercise Price Per Share, Exercised	34.87
Weighted - Average Exercise Price Per Share, Forfeited	37.70
Weighted - Average Exercise Price Per Share, Outstanding, Ending balance	35.46	$ 35.62
Weighted - Average Exercise Price Per Share, Vested and Exercisable at December 31, 2020	$ 35.46
Weighted - Average Remaining Contractual Term, Outstanding at December 31, 2019	3 years 4 months 6 days
Weighted - Average Remaining Contractual Term, Vested and Exercisable at December 31, 2020	3 years 4 months 6 days
Aggregate Intrinsic Value, Outstanding at December 31, 2019	$ 1,880
Aggregate Intrinsic Value, Vested and Exercisable at December 31, 2020	$ 1,880