Loans - Loan Balances by Loan Classification Allocated Between Past Due Performing and Non-performing (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	$ 528,994	$ 529,607
30 - 89 Days Past Due	8,741	1,855
Non-accrual Loans	5,029	7,422	$ 2,124
Special Mention	3,247	2,958
Impaired Loans Currently Performing Substandard	15,272	20,652
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	561,283	562,494
Multi-Family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	26,278	21,638
30 - 89 Days Past Due		6
Non-accrual Loans	1,926	1,968
Impaired Loans Currently Performing Substandard	1,107	1,113
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	29,311	24,725
One-to-Four Family Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	142,092	142,058
30 - 89 Days Past Due	928	671
Non-accrual Loans	198	2,234	1,235
Special Mention	102	41
Impaired Loans Currently Performing Substandard	2,616	995
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	145,936	145,999
Home Equity Line of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	32,002	33,396
30 - 89 Days Past Due	24	79
Non-accrual Loans	74	48
Special Mention	23
Impaired Loans Currently Performing Substandard	146	121
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	32,269	33,644
Junior Liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	1,573	1,720
Special Mention	34	35
Impaired Loans Currently Performing Substandard	16	16
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	1,623	1,771
Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	36,074	34,878
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	36,074	34,878
Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	11,440	11,047
30 - 89 Days Past Due	7,248	747
Non-accrual Loans	1,515	1,553
Special Mention	40	41
Impaired Loans Currently Performing Substandard	1,895	9,065
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	22,138	22,453
Farmland [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	40,901	41,853
30 - 89 Days Past Due	48	64
Non-accrual Loans	166	166
Impaired Loans Currently Performing Substandard	406	163
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	41,521	42,246
Non-Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	137,334	138,637
30 - 89 Days Past Due	137	228
Non-accrual Loans	28	247	542
Special Mention	2,737	2,489
Impaired Loans Currently Performing Substandard	8,056	8,110
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	148,292	149,711
Consumer Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	20,457	20,108
30 - 89 Days Past Due	23	15
Non-accrual Loans		8
Impaired Loans Currently Performing Substandard	284	193
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	20,764	20,324
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Currently Performing	80,843	84,272
30 - 89 Days Past Due	333	45
Non-accrual Loans	1,122	1,198	$ 347
Special Mention	311	352
Impaired Loans Currently Performing Substandard	746	876
Impaired Loans Currently Performing Doubtful	0	0
Total loans, gross	$ 83,355	$ 86,743