Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis (Detail) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Other real estate		$ 6,477	$ 7,298
Fair Value, Measurements, Nonrecurring [Member] | Models with Significant Unobservable Market Parameters (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Other real estate		6,477	7,298
Impaired loans, net	[1]	11,601	8,866
Total		18,078	16,164
Fair Value, Measurements, Nonrecurring [Member] | Reported Value Measurement [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Other real estate		6,477	7,298
Impaired loans, net	[1]	11,601	8,866
Total		$ 18,078	$ 16,164

[1] Amount is net of a valuation allowance of $0.9 million at June 30, 2015 and $1.6 million at December 31, 2014 as required by ASC 310, "Receivables."