OFF-BALANCE SHEET ARRANGEMENTS, COMMITMENTS AND CONTINGENCIES - Summary of Various Financial Instruments With Off-balance Sheet Risk Outstanding (Details) $ in Thousands	Sep. 30, 2018 USD ($)
Financial instruments with off-balance sheet risk
1 year or less	$ 300,337
More than 1 year but less than 3 years	208,642
3 years or more but less than 5 years	108,941
5 years or more	84,817
Total	702,737
Commitments to extend credit
Financial instruments with off-balance sheet risk
1 year or less	284,861
More than 1 year but less than 3 years	208,383
3 years or more but less than 5 years	108,841
5 years or more	84,337
Total	686,422
Standby and commercial letters of credit
Financial instruments with off-balance sheet risk
1 year or less	15,476
More than 1 year but less than 3 years	259
3 years or more but less than 5 years	100
5 years or more	480
Total	$ 16,315