Loans - Presentation of Age Analysis of Past-Due Loans, Segregated by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	$ 2,120	$ 3,343
60-89 Days Past Due	1,909	1,587
Greater than 90 Days Past Due	15,357	16,018
Total Past Due	19,386	20,948
Current Loans	1,165,434	1,143,935
Total loans	1,184,820	1,164,883
Commercial Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	48
Greater than 90 Days Past Due	9,555	9,582
Total Past Due	9,603	9,582
Current Loans	260,802	243,329
Total loans	270,405	252,911
Commercial Loans [Member] | Multifamily [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Greater than 90 Days Past Due	85	93
Total Past Due	85	93
Current Loans	63,512	60,453
Total loans	63,597	60,546
Commercial Loans [Member] | Nonresidential [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	48
Greater than 90 Days Past Due	3,872	3,891
Total Past Due	3,920	3,891
Current Loans	128,385	117,704
Total loans	132,305	121,595
Commercial Loans [Member] | Land [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Greater than 90 Days Past Due	531	531
Total Past Due	531	531
Current Loans	8,906	8,953
Total loans	9,437	9,484
Commercial Loans [Member] | Construction [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Greater than 90 Days Past Due	1,051	1,051
Total Past Due	1,051	1,051
Current Loans	9,979	15,013
Total loans	11,030	16,064
Commercial Loans [Member] | Secured [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Greater than 90 Days Past Due	4,016	4,016
Total Past Due	4,016	4,016
Current Loans	49,582	41,072
Total loans	53,598	45,088
Commercial Loans [Member] | Unsecured [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Loans	438	134
Total loans	438	134
Residential Mortgage Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	1,700	2,279
60-89 Days Past Due	1,111	605
Greater than 90 Days Past Due	4,261	4,856
Total Past Due	7,072	7,740
Current Loans	726,608	723,478
Total loans	733,680	731,218
Residential Mortgage Loans [Member] | Construction [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Loans	37,293	37,113
Total loans	37,293	37,113
Residential Mortgage Loans [Member] | One-to Four-Family [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	1,700	2,279
60-89 Days Past Due	1,111	605
Greater than 90 Days Past Due	4,261	4,856
Total Past Due	7,072	7,740
Current Loans	689,315	686,365
Total loans	696,387	694,105
Consumer Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	372	1,064
60-89 Days Past Due	798	982
Greater than 90 Days Past Due	1,541	1,580
Total Past Due	2,711	3,626
Current Loans	178,024	177,128
Total loans	180,735	180,754
Consumer Loans [Member] | Home Equity [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	360	588
60-89 Days Past Due	178	183
Greater than 90 Days Past Due	1,332	1,531
Total Past Due	1,870	2,302
Current Loans	153,132	152,474
Total loans	155,002	154,776
Consumer Loans [Member] | Automobile [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due		21
Greater than 90 Days Past Due	19	30
Total Past Due	19	51
Current Loans	7,135	5,851
Total loans	7,154	5,902
Consumer Loans [Member] | Marine [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
60-89 Days Past Due	164	686
Greater than 90 Days Past Due	144
Total Past Due	308	686
Current Loans	2,993	3,231
Total loans	3,301	3,917
Consumer Loans [Member] | Recreational Vehicle [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	11	452
60-89 Days Past Due	453	109
Greater than 90 Days Past Due	46	18
Total Past Due	510	579
Current Loans	12,937	13,475
Total loans	13,447	14,054
Consumer Loans [Member] | Other [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	1	3
60-89 Days Past Due	3	4
Greater than 90 Days Past Due		1
Total Past Due	4	8
Current Loans	1,827	2,097
Total loans	$ 1,831	$ 2,105