Loans Receivable, Net - Risk Category of Loans by Loan Portfolio Segment Excluding PCI Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Loan	$ 932,719	$ 733,897
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	803,340	649,951
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	129,379	83,946
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	887,931	694,680
Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	760,756	611,987
Pass [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	127,175	82,693
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	11,535	12,857
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	10,727	12,684
Special Mention [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	808	173
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	33,253	26,360
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	31,857	25,280
Substandard [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan	$ 1,396	$ 1,080