Loans - Past Due and Non-accrual Balances by Loan Classification (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	$ 483,346	$ 453,205
30-89 Days Past Due	3,389	2,491
Non-accrual Loans	11,812	7,663	12,119
Special Mention	10,508	13,511
Impaired Loans Currently Performing Substandard	28,601	58,617
Impaired Loans Currently Performing Doubtful
Total loans, gross	537,656	535,487
One-to-four Family Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	149,160	155,936
30-89 Days Past Due	2,172	1,339
Non-accrual Loans	1,131	2,243	2,577
Special Mention	1,169	779
Impaired Loans Currently Performing Substandard	4,248	2,038
Impaired Loans Currently Performing Doubtful
Total loans, gross	157,880	162,335
Home Equity Line of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	34,728	34,732
30-89 Days Past Due	289	5
Non-accrual Loans	22	66	91
Special Mention		1,109
Impaired Loans Currently Performing Substandard	943	1,171
Impaired Loans Currently Performing Doubtful
Total loans, gross	35,982	37,083
Junior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	3,355	3,584
30-89 Days Past Due	14	237
Non-accrual Loans	37	4	107
Special Mention	45	47
Impaired Loans Currently Performing Substandard	461	464
Impaired Loans Currently Performing Doubtful
Total loans, gross	3,912	4,336
Multi-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	27,870	27,463
Non-accrual Loans		38	190
Special Mention		1,478
Impaired Loans Currently Performing Substandard	2,095	4,077
Impaired Loans Currently Performing Doubtful
Total loans, gross	29,965	33,056
Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	8,818	13,876
30-89 Days Past Due		176
Non-accrual Loans
Special Mention	176
Impaired Loans Currently Performing Substandard		4,848
Impaired Loans Currently Performing Doubtful
Total loans, gross	8,994	18,900
Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	21,951	14,237
30-89 Days Past Due	235	137
Non-accrual Loans	2,255	2,768	4,290
Special Mention	7,441	7,683
Impaired Loans Currently Performing Substandard	7,263	21,081
Impaired Loans Currently Performing Doubtful
Total loans, gross	39,145	45,906
Non-Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	132,667	101,894
30-89 Days Past Due	206	293
Non-accrual Loans	7,055	1,134	4,000
Special Mention	890	669
Impaired Loans Currently Performing Substandard	6,673	18,647
Impaired Loans Currently Performing Doubtful
Total loans, gross	147,491	122,637
Consumer loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	12,345	13,266
30-89 Days Past Due	49	74
Non-accrual Loans	11	145
Impaired Loans Currently Performing Substandard	427	401
Impaired Loans Currently Performing Doubtful
Total loans, gross	12,832	13,886
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	47,366	43,961
30-89 Days Past Due	424	230
Non-accrual Loans	520	617	121
Special Mention	435	516
Impaired Loans Currently Performing Substandard	2,410	5,225
Impaired Loans Currently Performing Doubtful
Total loans, gross	51,155	50,549
Farmland [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	45,086	44,256
Non-accrual Loans	781	648	727
Special Mention	352	1,230
Impaired Loans Currently Performing Substandard	4,081	665
Impaired Loans Currently Performing Doubtful
Total loans, gross	$ 50,300	$ 46,799