GOODWILL AND OTHER INTANGIBLE ASSETS (Identifiable Intangible Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 75,209	$ 76,219
Accumulated Amortization	55,033	55,013
Gross Carrying Amount		76,219
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	27,801	27,801
Accumulated Amortization	23,829	23,721
Gross Carrying Amount		27,801
Customer Relationship Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	45,758	46,568
Accumulated Amortization	30,406	30,406
Gross Carrying Amount		46,568
Non-Solicitation Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,650	1,850
Accumulated Amortization	798	886
Gross Carrying Amount		1,850
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	688
Gross Carrying Amount	$ 688	$ 688