ALLOWANCE FOR CREDIT LOSSES (Allowance For Credit Losses By Segment, Class And Impairment Status) (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	$ 39,113,000	$ 51,392,000
Allowance for impaired loans and leases	3,711,000	2,350,000
Total allowance	125,887,000	126,458,000	$ 133,009,000	$ 142,443,000
Evaluated for impairment threshold	500,000
Commercial And Industrial [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	6,188,000	7,127,000
Allowance for impaired loans and leases	66,000	78,000
Allowance for all other loans and leases	17,779,000	17,505,000
Total allowance	17,845,000	17,583,000	23,830,000	21,419,000
Credit Cards [Member]
Financing Receivable, Impaired [Line Items]
Allowance for all other loans and leases	7,118,000	4,047,000
Total allowance	7,118,000	4,047,000	4,890,000	6,514,000
All Other [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans		103,000
Allowance for all other loans and leases	5,897,000	6,117,000
Total allowance	5,897,000	6,117,000	9,306,000	11,761,000
Consumer Mortgages [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	1,263,000	3,990,000
Allowance for impaired loans and leases	305,000
Allowance for all other loans and leases	31,314,000	33,198,000
Total allowance	31,619,000	33,198,000	33,644,000	40,015,000
Home Equity [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	1,487,000	1,795,000
Allowance for impaired loans and leases	732,000
Allowance for all other loans and leases	7,315,000	6,949,000
Total allowance	8,047,000	6,949,000	7,962,000	9,542,000
Agricultural [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	641,000	872,000
Allowance for impaired loans and leases		159,000
Allowance for all other loans and leases	2,152,000	2,365,000
Total allowance	2,152,000	2,524,000	2,515,000	3,420,000
Commercial And Industrial - Owner Occupied [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	9,285,000	12,141,000
Allowance for impaired loans and leases		326,000
Allowance for all other loans and leases	12,785,000	14,281,000
Total allowance	12,785,000	14,607,000	14,957,000	16,325,000
Construction, Acquisition And Development [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	6,339,000	7,583,000
Allowance for impaired loans and leases	48,000	677,000
Allowance for all other loans and leases	13,529,000	15,248,000
Total allowance	13,577,000	15,925,000	10,800,000	9,885,000
Commercial Real Estate [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	13,910,000	17,781,000
Allowance for impaired loans and leases	2,560,000	1,110,000
Allowance for all other loans and leases	24,287,000	24,398,000
Total allowance	$ 26,847,000	$ 25,508,000	$ 25,105,000	$ 23,562,000