Other Noninterest Income and Other Noninterest Expense - Summary of Other Noninterest Expense (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014
Other Income and Expenses [Abstract]
Lending and other client related processing costs		$ 3,608	$ 3,215	$ 10,861		$ 8,160
Telephone		2,224	1,931	6,727		5,217
Data processing services		2,083	2,229	5,274		6,497
Postage and supplies		728	763	2,220		2,248
Dues and publications		521	719	1,803		1,852
Other		5,106	4,711	15,216		9,381
Total other noninterest expense	[1]	$ 14,270	$ 13,568	$ 42,101	[2]	$ 33,355

[1] Prior period amounts have been revised to reflect the retrospective application of new accounting guidance adopted in the first quarter of 2015 related to our investments in qualified affordable housing projects (ASU 2014-01). See Note 1— "Basis of Presentation" of the "Notes to Interim Consolidated Financial Statements" under Part I, Item 1 in this report.

[2] Amounts for the nine months ended September 30, 2015, have been revised to reflect the retrospective application of new accounting guidance adopted in the second quarter of 2015 related to our consolidated variable interest entities (ASU 2015-02). Amounts prior to January 1, 2015 have not been revised for the adoption of this guidance. See Note 1— "Basis of Presentation” of the “Notes to Interim Consolidated Financial Statements (unaudited)” under Part I, Item 1 of this report for additional details.