Consolidated Condensed Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Assets:
Cash and due from banks	$ 108,528	$ 133,511
Money market instruments	471,957	104,188
Cash and cash equivalents	580,485	237,699
Investment securities:
Securities available-for-sale, at fair value (amortized cost of $1,251,451 and $1,299,980 at March 31, 2015 and December 31, 2014, respectively)	1,265,477	1,301,915
Securities held-to-maturity, at amortized cost (fair value of $136,418 and $143,490 at March 31, 2015 and December 31, 2014, respectively)	133,383	140,562
Other investment securities	58,311	58,311
Total investment securities	1,457,171	1,500,788
Loans	4,830,830	4,829,682
Allowance for loan losses	(55,408)	(54,352)
Net loans	4,775,422	4,775,330
Bank owned life insurance	168,585	171,928
Goodwill	72,334	72,334
Premises and equipment, net	57,189	55,479
Other real estate owned	26,337	22,605
Interest Receivable	17,979	17,677
Mortgage loan servicing rights	8,312	8,613
Other	140,185	138,746
Total assets	7,303,999	7,001,199
Liabilities and Shareholders' Equity:
Noninterest bearing	1,262,442	1,269,296
Interest bearing	4,253,405	3,858,704
Total deposits	5,515,847	5,128,000
Short-term borrowings	239,961	276,980
Long-term debt	733,555	786,602
Subordinated debentures and notes	45,000	45,000
Accrued interest payable	2,588	2,551
Other	59,617	65,525
Total liabilities	6,596,568	6,304,658
Shareholders' equity:
Preferred shares (200,000 shares authorized; 0 shares issued)	0	0
Common shares (No par value; 20,000,000 shares authorized; 16,150,876 shares issued at March 31, 2015 and 16,150,888 shares issued at December 31, 2014)	303,362	303,104
Retained earnings	489,040	484,484
Treasury shares (779,989 shares at March 31, 2015 and 758,489 at December 31, 2014)	(79,222)	(77,439)
Accumulated other comprehensive loss, net of taxes	(5,749)	(13,608)
Total shareholders' equity	707,431	696,541
Total liabilities and shareholders' equity	$ 7,303,999	$ 7,001,199