Contingencies and Concentrations Of Credit Risk - Additional Information (Details) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2016
USD ($)
| |
| Fair Value Concentration Of Risk Financial Statement Captions [Line Items] | |
| Regulatory lending percentage of bank's total capital | 15.00% |
| Peoples Intermountain Bank | |
| Fair Value Concentration Of Risk Financial Statement Captions [Line Items] | |
| Lending limit amount | $ 31.5 |
| Credit Concentration Risk | Real Estate Lending Arrangements | LTV Less than 80 Percent | |
| Fair Value Concentration Of Risk Financial Statement Captions [Line Items] | |
| Loan-to-value ratio | 80.00% |