Fair Value Measurements - Additional Information about Assets Measured at Fair Value on Non-Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Impaired loans	$ 12,117	$ 3,294
Other real estate owned	6,206	19,442
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Impaired loans
Other real estate owned
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Impaired loans	10,724	3,235
Other real estate owned	3,801	4,485
Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Impaired loans	1,393	59
Other real estate owned	$ 2,405	$ 14,957