Stock-Based Incentive Plan - Status of Options Granted Under Long-Term Incentive Plan (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Shares Under Option
Shares under option, outstanding, beginning balance | shares	597,405
Shares under option, expired | shares	(11,256)
Shares under option, forfeited | shares	(9,000)
Shares under option, exercised | shares	(69,038)
Share under option, outstanding, ending balance | shares	508,111
Shares under options, exercisable at December 31 | shares	344,850
Weighted Average Exercise Price Per Share [Abstract]
Weighted average exercise price per share, outstanding, beginning balance | $ / shares	$ 23.98
Weighted average exercise price per share, expired | $ / shares	24.23
Weighted average exercise price per share, forfeited | $ / shares	26.33
Weighted average exercise price per share, exercised | $ / shares	17.43
Weighted average exercise price per share, outstanding, ending balance | $ / shares	24.83
Weighted average exercise price per share, exercisable at December 31, 2019 | $ / shares	$ 23.14
Weighted average remaining contractual life, outstanding at December 31, 2019	6 years 7 months 6 days
Weighted average remaining contractual life, exercisable at December 31, 2019	6 years
Aggregate intrinsic value, outstanding at December 31, 2019 | $	$ 1,492
Aggregate intrinsic Value, exercisable at December 31, 2019 | $	$ 1,492