Regulatory Matters - Actual Capital Amounts and Ratios of Bank (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 210,457	$ 201,201
Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	126,274	120,720
Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	135,971	133,706
Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.00%	6.00%
Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%
Parent [Member]
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Actual, Amount	308,383	297,429
Tier 1 Capital (to Risk Weighted Assets), Actual, Amount	281,866	272,071
Tier 1 Capital (to Average Assets), Actual, Amount	281,866	272,071
Total Capital (to Risk Weighted Assets), Actual, Ratio	14.64%	14.77%
Tier 1 Capital (to Risk Weighted Assets), Actual, Ratio	13.39%	13.51%
Tier 1 Capital (to Average Assets), Actual, Ratio	10.36%	10.17%
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	168,466	161,064
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	84,233	80,532
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount	108,830	107,017
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	8.00%	8.00%
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	4.00%	4.00%
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio	4.00%	4.00%
Tri Countries Bank [Member]
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Actual, Amount	306,334	295,212
Tier 1 Capital (to Risk Weighted Assets), Actual, Amount	279,833	269,870
Tier 1 Capital (to Average Assets), Actual, Amount	279,833	269,870
Total Capital (to Risk Weighted Assets), Actual, Ratio	14.56%	14.67%
Tier 1 Capital (to Risk Weighted Assets), Actual, Ratio	13.30%	13.41%
Tier 1 Capital (to Average Assets), Actual, Ratio	10.29%	10.09%
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	168,366	160,961
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	84,183	80,480
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount	$ 108,777	$ 106,965
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	8.00%	8.00%
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	4.00%	4.00%
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio	4.00%	4.00%