Capital Requirements and Restrictions on Retained Earnings - Summary of Actual and Required Capital Amounts and Ratios (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Actual Amount	$ 212,711	$ 199,034
Total Capital to Risk Weighted Assets, Actual Ratio	13.18%	14.30%
Total Capital to Risk Weighted Assets, For Capital Adequacy Purposes Amount	$ 129,135	$ 111,374
Total Capital to Risk Weighted Assets, For Capital Adequacy Purposes Ratio	8.00%	8.00%
Tier 1 (Core) Capital to Risk Weighted Assets, Actual Amount	$ 195,974	$ 181,661
Tier 1 (Core) Capital to Risk Weighted Assets, Actual Ratio	12.14%	13.05%
Tier 1 (Core) Capital to Risk Weighted Assets, For Capital Adequacy Purposes Amount	$ 96,851	$ 55,687
Tier 1 (Core) Capital to Risk Weighted Assets, For Capital Adequacy Purposes Ratio	6.00%	4.00%
Common equity Tier 1 to Risk Weighted Assets, Actual Amount	$ 175,974
Common equity Tier 1 to Risk Weighted Assets, Actual Ratio	10.90%
Common equity Tier 1 to Risk Weighted Assets, For Capital Adequacy Purposes Amount	$ 72,638
Common equity Tier 1 to Risk Weighted Assets, For Capital Adequacy Purposes Ratio	4.50%
Tier 1 (Core) Capital to Average Assets, Actual Amount	$ 195,974	$ 181,661
Tier 1 (Core) Capital to Average Assets, Actual Ratio	8.73%	8.39%
Tier 1 (Core) Capital to Average Assets, For Capital Adequacy Purposes, Amount	$ 89,782	$ 86,641
Tier 1 (Core) Capital to Average Assets, For Capital Adequacy Purposes, Ratio	4.00%	4.00%
Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Actual Amount	$ 193,301	$ 180,597
Total Capital to Risk Weighted Assets, Actual Ratio	12.07%	13.16%
Total Capital to Risk Weighted Assets, For Capital Adequacy Purposes Amount	$ 128,132	$ 109,758
Total Capital to Risk Weighted Assets, For Capital Adequacy Purposes Ratio	8.00%	8.00%
Total Capital to Risk Weighted Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 160,166	$ 137,198
Total Capital to Risk Weighted Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00%	10.00%
Tier 1 (Core) Capital to Risk Weighted Assets, Actual Amount	$ 178,353	$ 164,835
Tier 1 (Core) Capital to Risk Weighted Assets, Actual Ratio	11.14%	12.01%
Tier 1 (Core) Capital to Risk Weighted Assets, For Capital Adequacy Purposes Amount	$ 96,099	$ 54,879
Tier 1 (Core) Capital to Risk Weighted Assets, For Capital Adequacy Purposes Ratio	6.00%	4.00%
Tier 1 (Core) Capital to Risk Weighted Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 128,132	$ 82,319
Tier 1 (Core) Capital to Risk Weighted Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	8.00%	6.00%
Common equity Tier 1 to Risk Weighted Assets, Actual Amount	$ 170,974
Common equity Tier 1 to Risk Weighted Assets, Actual Ratio	10.67%
Common equity Tier 1 to Risk Weighted Assets, For Capital Adequacy Purposes Amount	$ 72,074
Common equity Tier 1 to Risk Weighted Assets, For Capital Adequacy Purposes Ratio	4.50%
Common equity Tier 1 to Risk Weighted Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 104,108
Common equity Tier 1 to Risk Weighted Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.50%
Tier 1 (Core) Capital to Average Assets, Actual Amount	$ 178,353	$ 164,835
Tier 1 (Core) Capital to Average Assets, Actual Ratio	8.06%	7.71%
Tier 1 (Core) Capital to Average Assets, For Capital Adequacy Purposes, Amount	$ 88,464	$ 85,503
Tier 1 (Core) Capital to Average Assets, For Capital Adequacy Purposes, Ratio	4.00%	4.00%
Tier 1 (Core) Capital to Average Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 110,581	$ 106,878
Tier 1 (Core) Capital to Average Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%