Stock-Based Incentive Plan - Compensation Expense Related to Stock Incentive Plans Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-based compensation expense:
Total expense	$ 2,422	$ 2,625	$ 3,230
Tax benefit on nonqualified stock option expense, restricted stock awards and disqualifying dispositions of incentive stock options	518	620	1,432
Stock Options [Member]
Stock-based compensation expense:
Total expense	716	1,020	910
Restricted Stock Awards [Member]
Stock-based compensation expense:
Total expense		1,537	2,256
Restricted Stock Awards and Restricted Stock Units [Member]
Stock-based compensation expense:
Total expense	1,632
Employee Stock Purchase Plan [Member]
Stock-based compensation expense:
Total expense	$ 74	$ 68	$ 64