Loans Receivable, Net - Allowance for Loan Loses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method Excluding PCI Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for loan losses:
Balance at beginning of year	$ 16,317	$ 20,930	$ 20,510
Provision (benefit) charged to operations	1,275	2,630
Charge-offs	(1,135)	(7,827)	(3,521)
Recoveries	265	584	1,141
Balance at end of year	16,722	16,317	20,930
Loans:
Loans individually evaluated for impairment	38,372	36,979
Loans collectively evaluated for impairment	1,959,566	1,681,708
Total loans	1,997,938	1,718,687
Ending allowance balance attributed to loans:
Individually evaluated for impairment	1,339	2,161
Collectively evaluated for impairment	15,383	14,156
Total ending allowance balance	16,722	16,317
Residential Real Estate [Member]
Allowance for loan losses:
Balance at beginning of year	4,291	4,859
Provision (benefit) charged to operations	2,465	5,862
Charge-offs	(295)	(6,955)
Recoveries	129	525
Balance at end of year	6,590	4,291	4,859
Loans:
Loans individually evaluated for impairment	13,165	12,879
Loans collectively evaluated for impairment	828,841	772,562
Total loans	842,006	785,441
Ending allowance balance attributed to loans:
Individually evaluated for impairment	31	88
Collectively evaluated for impairment	6,559	4,203
Total ending allowance balance	6,590	4,291
Commercial Real Estate [Member]
Allowance for loan losses:
Balance at beginning of year	8,935	10,371
Provision (benefit) charged to operations	(1,696)	(1,122)
Charge-offs	(103)	(323)
Recoveries	29	9
Balance at end of year	7,165	8,935	10,371
Loans:
Loans individually evaluated for impairment	21,650	21,165
Loans collectively evaluated for impairment	796,584	628,786
Total loans	818,234	649,951
Ending allowance balance attributed to loans:
Individually evaluated for impairment	831	1,741
Collectively evaluated for impairment	6,334	7,194
Total ending allowance balance	7,165	8,935
Consumer [Member]
Allowance for loan losses:
Balance at beginning of year	1,146	1,360
Provision (benefit) charged to operations	529	211
Charge-offs	(678)	(471)
Recoveries	98	46
Balance at end of year	1,095	1,146	1,360
Loans:
Loans individually evaluated for impairment	2,307	2,221
Loans collectively evaluated for impairment	190,853	197,128
Total loans	193,160	199,349
Ending allowance balance attributed to loans:
Individually evaluated for impairment	43	332
Collectively evaluated for impairment	1,052	814
Total ending allowance balance	1,095	1,146
Commercial and Industrial [Member]
Allowance for loan losses:
Balance at beginning of year	863	1,383
Provision (benefit) charged to operations	826	(446)
Charge-offs	(59)	(78)
Recoveries	9	4
Balance at end of year	1,639	863	1,383
Loans:
Loans individually evaluated for impairment	1,250	714
Loans collectively evaluated for impairment	143,288	83,232
Total loans	144,538	83,946
Ending allowance balance attributed to loans:
Individually evaluated for impairment	434
Collectively evaluated for impairment	1,205	863
Total ending allowance balance	1,639	863
Unallocated [Member]
Allowance for loan losses:
Balance at beginning of year	1,082	2,957
Provision (benefit) charged to operations	(849)	(1,875)
Balance at end of year	233	1,082	$ 2,957
Ending allowance balance attributed to loans:
Collectively evaluated for impairment	233	1,082
Total ending allowance balance	$ 233	$ 1,082