GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 231,806	$ 221,526	$ 201,083
Other Intangible Assets	9,341	9,848
Total goodwill and other intangible assets	241,147	231,374
Core deposit intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Other Intangible Assets	8,636	8,527
Other identifiable Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Other Intangible Assets	$ 705	$ 1,321