ALLOWANCE FOR CREDIT LOSSES (Allowance For Credit Losses By Segment, Class And Impairment Status) (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	$ 41,897,000	$ 38,237,000
Allowance for impaired loans and leases	6,230,000	4,353,000
Total allowance		123,736,000	$ 126,506,000	$ 126,458,000
Evaluated for impairment threshold	500,000
Commercial And Industrial [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	11,838,000	8,314,000
Allowance for impaired loans and leases	3,482,000	1,837,000
Allowance for all other loans and leases	17,085,000	17,333,000
Total allowance	20,567,000	19,170,000	19,280,000	17,583,000
Credit Cards [Member]
Financing Receivable, Impaired [Line Items]
Allowance for all other loans and leases	6,166,000	7,787,000
Total allowance	6,166,000	7,787,000	3,240,000	4,047,000
All Other [Member]
Financing Receivable, Impaired [Line Items]
Allowance for all other loans and leases	4,385,000	5,346,000
Total allowance	4,385,000	5,346,000	6,380,000	6,117,000
Consumer Mortgages [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	1,276,000	1,655,000
Allowance for impaired loans and leases	7,000
Allowance for all other loans and leases	31,748,000	30,386,000
Total allowance	31,755,000	30,386,000	33,346,000	33,198,000
Home Equity [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	854,000	857,000
Allowance for impaired loans and leases	30,000
Allowance for all other loans and leases	7,002,000	7,174,000
Total allowance	7,032,000	7,174,000	7,033,000	6,949,000
Agricultural [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	3,592,000	861,000
Allowance for all other loans and leases	2,278,000	2,172,000
Total allowance	2,278,000	2,172,000	2,401,000	2,524,000
Commercial And Industrial - Owner Occupied [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	12,047,000	8,321,000
Allowance for impaired loans and leases	352,000
Allowance for all other loans and leases	13,514,000	12,899,000
Total allowance	13,866,000	12,899,000	14,749,000	14,607,000
Construction, Acquisition And Development [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	277,000	5,933,000
Allowance for impaired loans and leases	30,000	35,000
Allowance for all other loans and leases	13,455,000	13,922,000
Total allowance	13,485,000	13,957,000	14,664,000	15,925,000
Commercial Real Estate [Member] | Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	12,013,000	12,296,000
Allowance for impaired loans and leases	2,329,000	2,481,000
Allowance for all other loans and leases	23,333,000	22,364,000
Total allowance	$ 25,662,000	$ 24,845,000	$ 25,413,000	$ 25,508,000