DERIVATIVES - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) entity	Dec. 31, 2017 USD ($) entity
Derivative [Line Items]
Maximum derivative notional position as a percentage of assets	35.00%
Maximum credit exposure as a percentage of capital	3.00%
Maximum single counterparty credit risk exposure	$ 20,000
Inerest-bearing deposit liability	$ 1,816,432	$ 1,674,080
Number of counterparties | entity	14	13
Derivative Asset	$ 16,325	$ 12,682
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	16,327	12,687
Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	13,000	12,300
Other Credit Derivatives [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	10,100	15,400
Credit Risk Derivative Liabilities, at Fair Value	100	71
Credit Risk Contract [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	95,600	95,900
Accrued interest and other liabilities | Derivative [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	908,600	837,500
Derivative Asset	$ (10,400)
Derivative Financial Instruments, Liabilities, Fair Value Disclosure		$ 1,300