Stock-Based Incentive Plan - Compensation Expense Related to Stock Incentive Plans Recognized (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Share-based Payment Arrangement, Additional Disclosure [Abstract]
Total expense	$ 1,918	$ 1,972
Tax benefit on nonqualified stock option expense, restricted stock awards and disqualifying dispositions of incentive stock options	375	444
Stock Options [Member]
Share-based Payment Arrangement, Additional Disclosure [Abstract]
Total expense	274	546
Restricted Stock Awards and Restricted Stock Units [Member]
Share-based Payment Arrangement, Additional Disclosure [Abstract]
Total expense	1,579	1,372
Employee Stock Purchase Plan [Member]
Share-based Payment Arrangement, Additional Disclosure [Abstract]
Total expense	$ 65	$ 54