Loans Receivable and Allowance for Loan Losses - Summary of Loans and Leases Modified in Troubled Debt Restructurings and Recorded Investments (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Loan	Dec. 31, 2013 Loan
Financing Receivable, Modifications [Line Items]
Number of Loans	6	5
Recorded investment	$ 400	$ 400
TDRs in Compliance with Their Modified Terms and Accruing Interest
Financing Receivable, Modifications [Line Items]
Recorded investment	691	790
Number of loans and leases modified in troubled debt restructurings	15	9
TDRs in Compliance with Their Modified Terms and Accruing Interest | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Recorded investment	0	0
TDRs in Compliance with Their Modified Terms and Accruing Interest | Commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Recorded investment	0	0
TDRs in Compliance with Their Modified Terms and Accruing Interest | Construction
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Recorded investment	0	0
TDRs in Compliance with Their Modified Terms and Accruing Interest | Manufactured Housing
Financing Receivable, Modifications [Line Items]
Number of Loans	4	8
Recorded investment	231	758
TDRs in Compliance with Their Modified Terms and Accruing Interest | Residential Real Estate
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Recorded investment	0	0
TDRs in Compliance with Their Modified Terms and Accruing Interest | Home equity / other
Financing Receivable, Modifications [Line Items]
Number of Loans	11	1
Recorded investment	460	32
TDRs in Compliance with Their Modified Terms and Not Accruing Interest
Financing Receivable, Modifications [Line Items]
Recorded investment	389	448
Number of loans and leases modified in troubled debt restructurings	6	5
TDRs in Compliance with Their Modified Terms and Not Accruing Interest | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Recorded investment	0	0
TDRs in Compliance with Their Modified Terms and Not Accruing Interest | Commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Recorded investment	0	0
TDRs in Compliance with Their Modified Terms and Not Accruing Interest | Construction
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Recorded investment	0	0
TDRs in Compliance with Their Modified Terms and Not Accruing Interest | Manufactured Housing
Financing Receivable, Modifications [Line Items]
Number of Loans	6	5
Recorded investment	389	448
TDRs in Compliance with Their Modified Terms and Not Accruing Interest | Residential Real Estate
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Recorded investment	0	0
TDRs in Compliance with Their Modified Terms and Not Accruing Interest | Home equity / other
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Recorded investment	$ 0	$ 0