COMMITMENTS, CONTINGENCIES AND DERIVATIVES (Summary of Contractual and Notional Amounts of Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Customer Loan Swaps
Financial Instruments [Line Items]
Notional amount of derivative	$ 793,212	$ 703,336
Forward-Starting Interest Rate Swap
Financial Instruments [Line Items]
Notional amount of derivative	25,000	50,000
Interest rate swaps
Financial Instruments [Line Items]
Notional amount of derivative	43,000	43,000
Interest rate lock commitments
Financial Instruments [Line Items]
Notional amount of derivative	23,519	21,746
Forward Contracts [Member]
Financial Instruments [Line Items]
Notional amount of derivative	10,188	8,065
Other Commitments
Financial Instruments [Line Items]
Notional amount of derivative	2,478	523
Letters of Credit
Financial Instruments [Line Items]
Notional amount of derivative	2,676	2,848
Home Equity
Financial Instruments [Line Items]
Notional amount of derivative	495,086	477,401
Commercial and commercial real estate
Financial Instruments [Line Items]
Notional amount of derivative	29,443	49,482
Residential
Financial Instruments [Line Items]
Notional amount of derivative	$ 44,624	$ 41,368