Loans Receivable and Allowance for Loan Losses - Summary of Loans Modified in Troubled Debt Restructurings and Related Recorded Investment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Financing Receivable, Modifications [Line Items]
Recorded Investment	$ 200	$ 100
TDRs in Compliance with Their Modified Terms and Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	1	4
Recorded Investment	198	247
TDRs in Compliance with Their Modified Terms and Not Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	2	2
Recorded Investment	207	127
Commercial and industrial | TDRs in Compliance with Their Modified Terms and Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	0	0
Recorded Investment	0	0
Commercial and industrial | TDRs in Compliance with Their Modified Terms and Not Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	0	0
Recorded Investment	0	0
Commercial real estate | TDRs in Compliance with Their Modified Terms and Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	0	0
Recorded Investment	0	0
Commercial real estate | TDRs in Compliance with Their Modified Terms and Not Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	0	0
Recorded Investment	0	0
Construction | TDRs in Compliance with Their Modified Terms and Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	0	0
Recorded Investment	0	0
Construction | TDRs in Compliance with Their Modified Terms and Not Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	0	0
Recorded Investment	0	0
Manufactured housing | TDRs in Compliance with Their Modified Terms and Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	0	1
Recorded Investment	0	47
Manufactured housing | TDRs in Compliance with Their Modified Terms and Not Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	2	2
Recorded Investment	207	127
Residential real estate | TDRs in Compliance with Their Modified Terms and Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	1	3
Recorded Investment	198	200
Residential real estate | TDRs in Compliance with Their Modified Terms and Not Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	0	0
Recorded Investment	0	0
Other | TDRs in Compliance with Their Modified Terms and Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	0	0
Recorded Investment	0	0
Other | TDRs in Compliance with Their Modified Terms and Not Accruing Interest
Financing Receivable, Modifications [Line Items]
Number of loans modified in troubled debt restructurings	0	0
Recorded Investment	$ 0	$ 0