Commitments and Contingent Liabilities - Commitments to Extend Credit, Guarantees and Various Letters of Credit Outstanding (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Commitments And Contingencies Disclosure [Abstract]
Lines of credit	$ 936,986	$ 964,777
Loans approved but not closed	132,542	73,937
Overdraft limits	88,648	96,291
Letters of credit	26,212	18,686
Contingent obligations to purchase loans funded by other entities	$ 6,313	$ 6,327