Share-Based Compensation and Other Employee Benefit Plans - Compensation Expense Included in Non-Interest Expense and Related Income Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 1,408	$ 1,280	$ 1,470
Income tax benefit	103	93	124
Restricted Stock And Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	23,176	18,998	14,966
Income tax benefit	4,395	3,990	2,809
Phantom Stock and Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 10,160	$ 8,141	$ 10,756