Share-Based Compensation - Compensation Expense Included in Non-Interest Expense Related to Restricted Stock Awards and Restricted Share Units (Detail) (Restricted Stock Awards and Restricted Share Units [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Restricted Stock Awards and Restricted Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense related to restricted stock awards and restricted share units	$ 2,972	$ 2,316