Stock-Based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, expense	$ 3,272	$ 4,364	$ 5,784	$ 8,018
Income tax benefit	624	732	1,089	1,316
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, expense	0	379	0	761
Non-Vested Stock Awards/Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, expense	2,062	2,056	4,326	4,191
Director deferred stock units outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, expense	770	780	770	780
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, expense	$ 440	$ 1,149	$ 688	$ 2,286