ALLOWANCE FOR CREDIT LOSSES (Changes In The Allowance For Credit Losses By Segment And Class) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$ 126,458	$ 142,443	$ 142,443
Charge-offs	(3,243)	(4,780)	(26,719)
Recoveries	2,291	3,997	23,734
Provision	1,000	(5,000)	(13,000)
Balance at end of period	126,506	136,660	126,458
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	17,583	21,419	21,419
Charge-offs	(140)	(383)	(10,022)
Recoveries	212	502	2,035
Provision	1,625	(517)	4,151
Balance at end of period	19,280	21,021	17,583
Consumer Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	33,198	40,015	40,015
Charge-offs	(710)	(892)	(3,995)
Recoveries	455	612	2,693
Provision	403	(664)	(5,515)
Balance at end of period	33,346	39,071	33,198
Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	6,949	9,542	9,542
Charge-offs	(550)	(498)	(1,204)
Recoveries	80	241	639
Provision	554	261	(2,028)
Balance at end of period	7,033	9,546	6,949
Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	2,524	3,420	3,420
Charge-offs	(11)	(8)	(33)
Recoveries	36	269	384
Provision	(148)	(535)	(1,247)
Balance at end of period	2,401	3,146	2,524
Commercial And Industrial - Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	14,607	16,325	16,325
Charge-offs	(154)	(394)	(1,800)
Recoveries	125	550	2,834
Provision	171	(817)	(2,752)
Balance at end of period	14,749	15,664	14,607
Construction, Acquisition And Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	15,925	9,885	9,885
Charge-offs	(226)	(343)	(1,039)
Recoveries	272	604	11,727
Provision	(1,307)	(233)	(4,648)
Balance at end of period	14,664	9,913	15,925
Credit Cards [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	4,047	6,514	6,514
Charge-offs	(720)	(676)	(2,632)
Recoveries	181	153	658
Provision	(268)	(672)	(493)
Balance at end of period	3,240	5,319	4,047
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	25,508	23,562	23,562
Charge-offs	(245)	(1,007)	(3,723)
Recoveries	683	720	1,656
Provision	(533)	(1,773)	4,013
Balance at end of period	25,413	21,502	25,508
All Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	6,117	11,761	11,761
Charge-offs	(487)	(579)	(2,271)
Recoveries	247	346	1,108
Provision	503	(50)	(4,481)
Balance at end of period	$ 6,380	$ 11,478	$ 6,117