Employee Benefit Plans - Summary of Activity for the Stock Option Component of the Incentive Plan (Detail)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Compensation Related Costs [Abstract]
Number of options, Outstanding at beginning of the year | shares	733,440
Number of options, Granted during the year | shares	142,600
Number of options, Exercised during the year | shares	(61,623)
Number of options, Forfeited or expired during the year | shares	(39,668)
Number of options, Outstanding at end of the year | shares	774,749
Number of options, Exercisable at year end | shares	703,636
Weighted average exercise price per share, Outstanding at beginning of the year | $ / shares	$ 33.06
Weighted average exercise price per share, Granted during the year | $ / shares	21.55
Weighted average exercise price per share, Exercised during the year | $ / shares	15.93
Weighted average exercise price per share, Forfeited or expired during the year | $ / shares	22.03
Weighted average exercise price per share, Outstanding at end of the year | $ / shares	32.87
Weighted average exercise price per share, Exercisable at year end | $ / shares	$ 34.01