OFF-BALANCE SHEET ARRANGEMENTS, COMMITMENTS AND CONTINGENCIES - Summary of Various Financial Instruments With Off-balance Sheet Risk Outstanding (Details) $ in Thousands	Mar. 31, 2018 USD ($)
Financial instruments with off-balance sheet risk
1 year or less	$ 288,939
More than 1 year but less than 3 years	201,646
3 years or more but less than 5 years	55,642
5 years or more	87,851
Total	634,078
Commitments to extend credit
Financial instruments with off-balance sheet risk
1 year or less	278,358
More than 1 year but less than 3 years	201,172
3 years or more but less than 5 years	55,542
5 years or more	87,211
Total	622,283
Standby and commercial letters of credit
Financial instruments with off-balance sheet risk
1 year or less	10,581
More than 1 year but less than 3 years	474
3 years or more but less than 5 years	100
5 years or more	640
Total	$ 11,795