DERIVATIVES - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($) entity	Dec. 31, 2016 USD ($) 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	$ 1,547,892	$ 1,354,056
Number of counterparties | entity	10	10
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	$ 13,078	$ 12,587
Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	17,800	13,200
Other Credit Derivatives [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	21,300	17,800
Credit Risk Derivative Liabilities, at Fair Value	100	200
Credit Risk Contract [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	68,000	64,900
Accrued interest and other liabilities | Derivative [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	773,900	677,800
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	$ 3,000	$ 5,200