Stock-Based Incentive Plan - Status of Options Granted Under Long-Term Incentive Plan (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Shares Under Option
Shares under option, outstanding, beginning balance | shares	508,111
Shares under option, expired | shares	(500)
Shares under option, forfeited | shares	(3,152)
Shares under option, exercised | shares	(5,000)
Shares under option, outstanding, ending balance | shares	499,459
Shares under options, exercisable at March 31, 2020 | shares	445,481
Weighted Average Exercise Price Per Share [Abstract]
Weighted average exercise price per share, outstanding, beginning balance | $ / shares	$ 24.83
Weighted average exercise price per share, outstanding, expired | $ / shares	28.50
Weighted average exercise price per share, outstanding, forfeited | $ / shares	28.44
Weighted average exercise price per share, outstanding, exercised | $ / shares	18.70
Weighted average exercise price per share, outstanding, ending balance | $ / shares	24.86
Weighted average exercise price per share, exercisable at March 31, 2020 | $ / shares	$ 24.42
Weighted average remaining contractual life, outstanding at March 31, 2020	6 years 2 months 12 days
Weighted average remaining contractual life, exerciseable at March 31, 2020	6 years
Aggregated intrinsic value, outstanding at March 31, 2020 | $	$ 5
Aggregated intrinsic value, exercisable at March 31, 2020 | $	$ 5