Loans - Presentation of Age Analysis of Past-Due Loans, Segregated by Class of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	$ 17,806	$ 20,948
Current Loans	1,222,581	1,143,935
Total loans	1,240,387	1,164,883
30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	2,228	3,343
60-89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,332	1,587
Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	14,246	16,018
Commercial Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	8,808	9,582
Current Loans	304,467	243,329
Total loans	313,275	252,911
Commercial Loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	13
Commercial Loans [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	8,795	9,582
Commercial Loans [Member] | Multifamily [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	85	93
Current Loans	69,400	60,453
Total loans	69,485	60,546
Commercial Loans [Member] | Multifamily [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	85	93
Commercial Loans [Member] | Nonresidential [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	3,796	3,891
Current Loans	144,229	117,704
Total loans	148,025	121,595
Commercial Loans [Member] | Nonresidential [Member] | 30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	13
Commercial Loans [Member] | Nonresidential [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	3,783	3,891
Commercial Loans [Member] | Land [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	496	531
Current Loans	9,735	8,953
Total loans	10,231	9,484
Commercial Loans [Member] | Land [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	496	531
Commercial Loans [Member] | Construction [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	415	1,051
Current Loans	15,850	15,013
Total loans	16,265	16,064
Commercial Loans [Member] | Construction [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	415	1,051
Commercial Loans [Member] | Secured [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	4,016	4,016
Current Loans	64,797	41,072
Total loans	68,813	45,088
Commercial Loans [Member] | Secured [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	4,016	4,016
Commercial Loans [Member] | Unsecured [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Loans	456	134
Total loans	456	134
Residential Mortgage Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	6,257	7,740
Current Loans	737,159	723,478
Total loans	743,416	731,218
Residential Mortgage Loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,414	2,279
Residential Mortgage Loans [Member] | 60-89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	636	605
Residential Mortgage Loans [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	4,207	4,856
Residential Mortgage Loans [Member] | Construction [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Loans	34,074	37,113
Total loans	34,074	37,113
Residential Mortgage Loans [Member] | One-to Four-Family [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	6,257	7,740
Current Loans	703,085	686,365
Total loans	709,342	694,105
Residential Mortgage Loans [Member] | One-to Four-Family [Member] | 30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,414	2,279
Residential Mortgage Loans [Member] | One-to Four-Family [Member] | 60-89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	636	605
Residential Mortgage Loans [Member] | One-to Four-Family [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	4,207	4,856
Consumer Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	2,741	3,626
Current Loans	180,955	177,128
Total loans	183,696	180,754
Consumer Loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	801	1,064
Consumer Loans [Member] | 60-89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	696	982
Consumer Loans [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,244	1,580
Consumer Loans [Member] | Home Equity [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,730	2,302
Current Loans	156,179	152,474
Total loans	157,909	154,776
Consumer Loans [Member] | Home Equity [Member] | 30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	472	588
Consumer Loans [Member] | Home Equity [Member] | 60-89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	136	183
Consumer Loans [Member] | Home Equity [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,122	1,531
Consumer Loans [Member] | Automobile [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	20	51
Current Loans	8,149	5,851
Total loans	8,169	5,902
Consumer Loans [Member] | Automobile [Member] | 30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	9	21
Consumer Loans [Member] | Automobile [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	11	30
Consumer Loans [Member] | Marine [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	382	686
Current Loans	2,672	3,231
Total loans	3,054	3,917
Consumer Loans [Member] | Marine [Member] | 30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	287
Consumer Loans [Member] | Marine [Member] | 60-89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		686
Consumer Loans [Member] | Marine [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	95
Consumer Loans [Member] | Recreational Vehicle [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	606	579
Current Loans	12,005	13,475
Total loans	12,611	14,054
Consumer Loans [Member] | Recreational Vehicle [Member] | 30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	33	452
Consumer Loans [Member] | Recreational Vehicle [Member] | 60-89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	557	109
Consumer Loans [Member] | Recreational Vehicle [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	16	18
Consumer Loans [Member] | Other [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	3	8
Current Loans	1,950	2,097
Total loans	1,953	2,105
Consumer Loans [Member] | Other [Member] | 30-59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		3
Consumer Loans [Member] | Other [Member] | 60-89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	$ 3	4
Consumer Loans [Member] | Other [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		$ 1