REGULATORY MATTERS - Bank's actual capital amounts and ratios (Details) - USD ($)
$ in Thousands |
Mar. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
| Banking and Thrift [Abstract] |
|
|
|
| Total Capital to Risk-Weighted Assets, Actual Capital, Amount |
$ 131,884
|
$ 128,939
|
$ 116,869
|
| Total Capital to Risk-Weighted Assets, Actual Capital, Ratio |
14.50%
|
14.55%
|
14.96%
|
| Total Capital to Risk-Weighted Assets, For Capital Adequacy Purposes, Amount |
$ 73,014
|
$ 70,891
|
$ 62,514
|
| Total Capital to Risk-Weighted Assets, For Capital Adequacy Purposes, Ratio |
8.00%
|
8.00%
|
8.00%
|
| Total Capital to Risk-Weighted Assets, To be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
$ 91,267
|
$ 88,614
|
$ 78,142
|
| Total Capital to Risk-Weighted Assets, To be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
10.00%
|
10.00%
|
10.00%
|
| Tier I Capital to Risk-Weighted Assets, Actual Capital, Amount |
$ 120,471
|
$ 117,855
|
$ 107,112
|
| Tier I Capital to Risk-Weighted Assets, Actual Capital, Ratio |
13.20%
|
13.30%
|
13.71%
|
| Tier I Capital to Risk-Weighted Assets, For Capital Adequacy Purposes, Amount |
$ 54,760
|
$ 53,168
|
$ 46,885
|
| Tier I Capital to Risk-Weighted Assets, For Capital Adequacy Purposes, Ratio |
6.00%
|
6.00%
|
6.00%
|
| Tier I Capital to Risk-Weighted Assets, To be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
$ 73,014
|
$ 70,891
|
$ 62,514
|
| Tier I Capital to Risk-Weighted AssetsTo be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
8.00%
|
8.00%
|
8.00%
|
| Common Equity Tier 1 Capital to Risk-Weighted Assets, Actual Capital, Amount |
$ 107,112
|
$ 117,855
|
$ 107,112
|
| Common Equity Tier 1 Capital to Risk-Weighted Assets, Actual Capital, Ratio |
13.71%
|
13.30%
|
13.71%
|
| Common Equity Tier 1 Capital to Risk-Weighted Assets, For Capital Adequacy Purposes, Amount |
$ 35,164
|
$ 39,876
|
$ 35,164
|
| Common Equity Tier 1 Capital to Risk-Weighted Assets, For Capital Adequacy Purposes, Ratio |
4.50%
|
4.50%
|
4.50%
|
| Common Equity Tier 1 Capital to Risk-Weighted Assets, To be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
$ 50,792
|
$ 57,599
|
$ 50,792
|
| Common Equity Tier 1 Capital to Risk-Weighted Assets, To be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
6.50%
|
6.50%
|
6.50%
|
| Tier I Capital to Average Assets, Actual Capital, Amount |
$ 120,471
|
$ 117,855
|
$ 107,112
|
| Tier I Capital to Average Assets, Actual Capital, Ratio |
12.20%
|
12.69%
|
11.80%
|
| Tier I Capital to Average Assets, For Capital Adequacy Purposes, Amount |
$ 39,512
|
$ 37,157
|
$ 36,299
|
| Tier I Capital to Average Assets, For Capital Adequacy Purposes, Ratio |
4.00%
|
4.00%
|
4.00%
|
| Tier I Capital to Average Assets, To be Well Capitalized Under Prompt Corrective Action Provisions, Amount |
$ 49,391
|
$ 46,446
|
$ 45,374
|
| Tier I Capital to Average Assets, To be Well Capitalized Under Prompt Corrective Action Provisions, Ratio |
5.00%
|
5.00%
|
5.00%
|