| Component: (Network and Table) | |
|---|---|
| Network | 2414403 - Disclosure - STOCK BASED COMPENSATION - Summary of Stock Option Valuation Assumptions (Details) (http://www.allegiancebank.com/role/StockBasedCompensationSummaryOfStockOptionValuationAssumptionsDetails) |
| Table | Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] |
| Reporting Entity [Axis] | 0001642081 (http://www.sec.gov/CIK) |
| Plan Name [Axis] | Stock Option Plan |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | Period [Axis] | ||
|---|---|---|---|
2016-01-01 - 2016-12-31 | 2015-01-01 - 2015-12-31 | 2014-01-01 - 2014-12-31 | |
Risk-free interest rate | |||
Expected term | |||
Expected stock price volatility | |||
Dividend yield | |||