Stock-Based Compensation - Schedule of Outstanding Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2021 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options, Outstanding at beginning | shares	200,000	305,000
Options, Granted | shares	0	0
Options, Exercised | shares	(100,000)	(170,000)
Options, Forfeited or expired | shares	0	(35,000)
Options, Outstanding at ending | shares	100,000	100,000
Weighted Average Exercise Price, Outstanding at beginning	$ 34.55	$ 27.94
Weighted Average Exercise Price, Granted	0	0
Weighted Average Exercise Price, Exercised	29.55	23.71
Weighted Average Exercise Price, Forfeited or expired	0	15.36
Weighted Average Exercise Price, Outstanding at ending	39.54	39.54
Weighted Average Grant Date Fair Value, Outstanding at beginning	15.43	12.65
Weighted Average Grant Date Fair Value, Granted	0	0
Weighted Average Grant Date Fair Value, Exercised	19.79	15.93
Weighted Average Grant Date Fair Value, Forfeited or expired	0	7.36
Weighted Average Grant Date Fair Value, Outstanding at ending	$ 22.23	$ 22.23
Aggregate Intrinsic Value, Outstanding | $	$ 0	$ 0
Options, Exercisable at ending | shares	100,000	100,000
Weighted Average Exercise Price, Exercisable at ending	$ 39.54	$ 39.54
Aggregate Intrinsic Value, Exercisable | $	$ 0	$ 0