GOODWILL, OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Mortgage Servicing Rights) (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2018		Jun. 30, 2017		Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Servicing Asset at Amortized Value, Balance [Roll Forward]
Servicing Asset at Amortized Cost, Additions, Acquisitions		$ 30		$ 0			$ 0
Mortgage Servicing Rights [Member]
Morgage Servicing Rights at Amortized Value [Line Items]
Loans Serviced For Others		2,260,000				$ 2,260,000		$ 2,190,000
Custodial Accounts		14,300				14,300		$ 10,200
Servicing Asset at Amortized Value, Balance [Roll Forward]
Balance, net of valuation allowance, beginning of the period		14,617		15,272		14,738	15,249
Additions—amounts capitalized		863		706		1,684	1,651
Amortization		(989)	[1]	(993)	[1]	(1,946)	(1,915)
Balance, net of valuation allowance, end of the period	[2]	14,521		$ 14,985		14,521	$ 14,985
Valuation allowance, end of period		$ 0				$ 0

[1] Amortization of mortgage servicing rights is recorded as a reduction of loan servicing income within mortgage banking operations and any unamortized balance is fully amortized if the loan repays in full.

[2] There was no valuation allowance as of June 30, 2018 and 2017.