FAIR VALUE MEASUREMENTS - Valuation methodology and unobservable inputs for Level 3 assets (Details 2) - Nonrecurring basis - USD ($) $ in Thousands |
Mar. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|---|
| Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | |||
| Impaired loans, fair value | $ 4,476 | $ 659 | $ 3,670 |
| Level 3 | |||
| Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | |||
| Impaired loans, fair value | $ 4,476 | $ 659 | $ 3,670 |