Regulatory Matters - Actual and Required Capital Ratios of Bank (Detail) - USD ($)
$ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Schedule of Capitalization [Line Items] |
|
|
| Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
|
$ 279,311
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
|
167,587
|
| Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
|
$ 185,918
|
| Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
|
10.00%
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
|
6.00%
|
| Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
|
5.00%
|
| Parent [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Total Capital (to Risk Weighted Assets), Actual, Amount |
$ 474,436
|
$ 436,955
|
| Tier 1 Capital (to Risk Weighted Assets), Actual, Amount |
435,950
|
401,971
|
| Tier 1 Capital (to Average Assets), Actual, Amount |
$ 435,950
|
$ 401,971
|
| Total Capital (to Risk Weighted Assets), Actual, Ratio |
15.09%
|
15.63%
|
| Tier 1 Capital (to Risk Weighted Assets), Actual, Ratio |
13.86%
|
14.38%
|
| Tier 1 Capital (to Average Assets), Actual, Ratio |
10.79%
|
10.80%
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
|
$ 223,603
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
|
111,801
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount |
|
$ 148,819
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
|
8.00%
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
|
4.00%
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio |
|
4.00%
|
| Parent [Member] | Basel III Phase-in Schedule [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
$ 251,555
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
188,666
|
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount |
$ 161,562
|
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
8.00%
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
6.00%
|
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio |
4.00%
|
|
| Parent [Member] | Basel III Fully Phased In [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
$ 330,165
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
267,277
|
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount |
$ 161,562
|
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
10.50%
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
8.50%
|
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio |
4.00%
|
|
| Parent [Member] | Common Stock [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Tier 1 Capital (to Risk Weighted Assets), Actual, Amount |
$ 385,747
|
|
| Tier 1 Capital (to Risk Weighted Assets), Actual, Ratio |
12.27%
|
|
| Parent [Member] | Common Stock [Member] | Basel III Phase-in Schedule [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
$ 141,499
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
4.50%
|
|
| Parent [Member] | Common Stock [Member] | Basel III Fully Phased In [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
$ 220,110
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
7.00%
|
|
| Tri Countries Bank [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Total Capital (to Risk Weighted Assets), Actual, Amount |
$ 473,327
|
$ 433,286
|
| Tier 1 Capital (to Risk Weighted Assets), Actual, Amount |
434,841
|
398,325
|
| Tier 1 Capital (to Average Assets), Actual, Amount |
$ 434,841
|
$ 398,325
|
| Total Capital (to Risk Weighted Assets), Actual, Ratio |
15.06%
|
15.51%
|
| Tier 1 Capital (to Risk Weighted Assets), Actual, Ratio |
13.84%
|
14.26%
|
| Tier 1 Capital (to Average Assets), Actual, Ratio |
10.76%
|
10.71%
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
|
$ 223,449
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
|
111,724
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount |
|
$ 148,734
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
|
8.00%
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
|
4.00%
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio |
|
4.00%
|
| Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
$ 314,272
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
251,418
|
|
| Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
$ 202,002
|
|
| Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
10.00%
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
8.00%
|
|
| Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
5.00%
|
|
| Tri Countries Bank [Member] | Basel III Phase-in Schedule [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
$ 251,418
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
188,563
|
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount |
$ 161,601
|
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
8.00%
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
6.00%
|
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio |
4.00%
|
|
| Tri Countries Bank [Member] | Basel III Fully Phased In [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
$ 329,985
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
267,131
|
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount |
$ 161,601
|
|
| Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
10.50%
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
8.50%
|
|
| Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio |
4.00%
|
|
| Tri Countries Bank [Member] | Common Stock [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Tier 1 Capital (to Risk Weighted Assets), Actual, Amount |
$ 434,841
|
|
| Tier 1 Capital (to Risk Weighted Assets), Actual, Ratio |
13.84%
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
$ 204,277
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
6.50%
|
|
| Tri Countries Bank [Member] | Common Stock [Member] | Basel III Phase-in Schedule [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
$ 141,422
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
4.50%
|
|
| Tri Countries Bank [Member] | Common Stock [Member] | Basel III Fully Phased In [Member] |
|
|
| Schedule of Capitalization [Line Items] |
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount |
$ 219,990
|
|
| Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio |
7.00%
|
|