Modifications of Loans Performing (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Financing Receivable Recorded Investment Past Due [Line Items]
Past Due 30-89	$ 2,567	$ 7,163
Past Due 90 days and still accuring	426	669
Non- Accrual	5,995	6,056	33,000
Total	716,359	704,531
Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Current Loans	2,629	2,880
Past Due 30-89	0	622
Past Due 90 days and still accuring	0	0
Non- Accrual	4,062	3,281
Total	6,691	6,783
Allowance for loan losses, Current Loans	108	120
Allowance for loan losses, Past Due 30-89	0	11
Allowance for loan losses, Past Due 90 days and still accruing	0	103
Allowance for loan losses, Non-Accural	192	0
Allowance for loan losses, Total	300	234
Loans | Commercial installment
Financing Receivable Recorded Investment Past Due [Line Items]
Current Loans	229	233
Past Due 30-89	0	0
Past Due 90 days and still accuring	0	0
Non- Accrual	0	0
Total	229	233
Loans | Commercial real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Current Loans	1,680	1,685
Past Due 30-89	0	0
Past Due 90 days and still accuring	0	0
Non- Accrual	2,695	2,729
Total	4,375	4,414
Loans | Consumer real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Current Loans	711	952
Past Due 30-89	0	622
Past Due 90 days and still accuring	0	0
Non- Accrual	1,273	449
Total	1,984	2,023
Loans | Commercial installment
Financing Receivable Recorded Investment Past Due [Line Items]
Current Loans	9	10
Past Due 30-89	0	0
Past Due 90 days and still accuring	0	0
Non- Accrual	94	103
Total	$ 103	$ 113