GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 506,206	$ 256,105	$ 231,806
Other Intangible Assets	29,286	15,250
Total goodwill and other intangible assets	535,492	271,355
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Other Intangible Assets	28,016	13,692
Other identifiable Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Other Intangible Assets	$ 1,270	$ 1,558