Fair Value Measurement - Assets and Liabilities Measured on Non-recurring Basis (Detail) - Fair Value, Measurements, Nonrecurring [Member] - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Commercial Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	$ 3,305	$ 3,803
Commercial Loans [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	3,305	3,803
Consumer Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	306	260
Consumer Loans [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	306	260
Construction Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other real estate owned, net	804	1,286
Construction Loans [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other real estate owned, net	804	1,286
Non Residential Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other real estate owned, net	175
Non Residential Loans [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other real estate owned, net	175
Residential Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	601	765
Other real estate owned, net	588	640
Residential Loans [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	601	765
Other real estate owned, net	$ 588	$ 640