Fair Value - Schedule of Financial Assets Measured at Fair Value on Nonrecurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Collateral-dependent impaired loans	$ 34,482	$ 24,392
Other real estate owned	20,742	25,525
Total nonrecurring fair value measurements	55,224	49,917
Level 1 [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Collateral-dependent impaired loans
Other real estate owned
Total nonrecurring fair value measurements
Level 2 [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Collateral-dependent impaired loans	34,482	24,392
Other real estate owned
Total nonrecurring fair value measurements	34,482	24,392
Level 3 [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Collateral-dependent impaired loans
Other real estate owned	20,742	25,525
Total nonrecurring fair value measurements	$ 20,742	$ 25,525