Loans Receivable - Changes in Allowance for Loan Losses and Recorded Investment in Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 6,718	$ 6,721	$ 6,805	$ 6,709
Charge-offs	85	117	205	273
Recoveries	33	49	156	67
Provision	150	75	60	225
Ending Balance	6,816	6,728	6,816	6,728
Ending balance: individually evaluated for impairment	1,351		1,351		1,061
Ending balance: collectively evaluated for impairment	5,465		5,465		5,744
Loans Receivable:
Ending Balance	6,816	6,728	6,816	6,728
Ending balance: individually evaluated for impairment	1,351		1,351		1,061
Ending balance: collectively evaluated for impairment	5,465		5,465		5,744
Ending Balance	726,571		726,571		716,239
Ending balance: individually evaluated for impairment	16,830		16,830		17,022
Ending balance: collectively evaluated for impairment	709,741		709,741		699,217
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	535	556	523	550
Charge-offs
Recoveries	10		103
Provision	(74)	(13)	(155)	(7)
Ending Balance	471	543	471	543
Ending balance: individually evaluated for impairment	56		56		24
Ending balance: collectively evaluated for impairment	415		415		499
Loans Receivable:
Ending Balance	471	543	471	543
Ending balance: individually evaluated for impairment	56		56		24
Ending balance: collectively evaluated for impairment	415		415		499
Ending Balance	55,071		55,071		52,801
Ending balance: individually evaluated for impairment	56		56		24
Ending balance: collectively evaluated for impairment	55,015		55,015		52,777
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,832	2,197	1,723	2,075
Charge-offs		7		7
Recoveries
Provision	(96)	(88)	13	34
Ending Balance	1,736	2,102	1,736	2,102
Ending balance: individually evaluated for impairment	847		847		989
Ending balance: collectively evaluated for impairment	889		889		734
Loans Receivable:
Ending Balance	1,736	2,102	1,736	2,102
Ending balance: individually evaluated for impairment	847		847		989
Ending balance: collectively evaluated for impairment	889		889		734
Ending Balance	101,545		101,545		103,337
Ending balance: individually evaluated for impairment	13,957		13,957		14,385
Ending balance: collectively evaluated for impairment	87,588		87,588		88,952
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,045	1,064	1,054	1,031
Charge-offs	59	107	171	253
Recoveries	23	49	53	67
Provision	63	56	136	217
Ending Balance	1,072	1,062	1,072	1,062
Ending balance: individually evaluated for impairment	47		47		48
Ending balance: collectively evaluated for impairment	1,025		1,025		1,006
Loans Receivable:
Ending Balance	1,072	1,062	1,072	1,062
Ending balance: individually evaluated for impairment	47		47		48
Ending balance: collectively evaluated for impairment	1,025		1,025		1,006
Ending Balance	139,988		139,988		136,142
Ending balance: individually evaluated for impairment	461		461		407
Ending balance: collectively evaluated for impairment	139,527		139,527		135,735
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	2,786	2,389	2,996	2,541
Charge-offs	26	1	34	11
Recoveries
Provision	384	37	182	(105)
Ending Balance	3,144	2,425	3,144	2,425
Ending balance: individually evaluated for impairment	401		401
Ending balance: collectively evaluated for impairment	2,743		2,743		2,996
Loans Receivable:
Ending Balance	3,144	2,425	3,144	2,425
Ending balance: individually evaluated for impairment	401		401
Ending balance: collectively evaluated for impairment	2,743		2,743		2,996
Ending Balance	429,967		429,967		423,959
Ending balance: individually evaluated for impairment	2,356		2,356		2,206
Ending balance: collectively evaluated for impairment	427,611		427,611		421,753
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	520	515	509	512
Charge-offs		2		2
Recoveries
Provision	(127)	83	(116)	86
Ending Balance	393	596	393	596
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	393		393		509
Loans Receivable:
Ending Balance	393	596	393	596
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	393		393		509
Ending Balance
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment