GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 50,686	$ 50,345
Accumulated Amortization	(40,345)	(38,546)
Net Carrying Amount	10,341	11,799
Estimated aggregate amortization expense [Abstract]
Jul - Dec 2015	1,647
2016	2,683
2017	1,970
2018	1,476
2019	1,044
Thereafter	1,521
Net Carrying Amount	10,341	11,799
Components of goodwill [Abstract]
Goodwill	379,998	379,998
Goodwill, Activity	0
Accumulated impairment	(4,824)	(4,824)
Accumulated impairment, Activity	0
Goodwill, net	375,174	375,174	$ 375,174
Goodwill, net, Activity	0
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	40,326	40,326
Accumulated Amortization	(31,752)	(30,303)
Net Carrying Amount	8,574	10,023
Estimated aggregate amortization expense [Abstract]
Net Carrying Amount	8,574	10,023
Other Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	10,360	10,019
Accumulated Amortization	(8,593)	(8,243)
Net Carrying Amount	1,767	1,776
Estimated aggregate amortization expense [Abstract]
Net Carrying Amount	$ 1,767	$ 1,776