Consolidated Condensed Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Assets:
Cash and due from banks	$ 99,976	$ 164,120
Money market instruments	420,536	37,185
Cash and cash equivalents	520,512	201,305
Investment securities:
Securities available-for-sale, at fair value (amortized cost of $990,116 and $1,099,658 at March 31, 2013 and December 31, 2012)	1,001,251	1,114,454
Securities held-to-maturity, at amortized cost (fair value of $294,314 and $410,705 at March 31, 2013 and December 31, 2012)	285,250	401,390
Other investment securities	65,907	65,907
Total investment securities	1,352,408	1,581,751
Loans	4,443,523	4,450,322
Allowance for loan losses	(55,315)	(55,537)
Net loans	4,388,208	4,394,785
Bank owned life insurance	166,651	161,069
Goodwill and other intangible assets	72,559	72,671
Bank premises and equipment, net	56,725	53,751
Other real estate owned	36,292	35,718
Accrued interest receivable	18,571	19,710
Mortgage loan servicing rights	8,121	7,763
Other	127,108	114,280
Total assets	6,747,155	6,642,803
Liabilities and Stockholders' Equity:
Noninterest bearing	1,119,902	1,137,290
Interest bearing	3,796,639	3,578,742
Total deposits	4,916,541	4,716,032
Short-term borrowings	244,002	344,168
Long-term debt	782,845	781,658
Subordinated debentures and notes	80,250	80,250
Accrued interest payable	3,403	3,459
Other	65,904	66,870
Total liabilities	6,092,945	5,992,437
COMMITMENTS AND CONTINGENCIES
Stockholders' equity:
Common stock (No par value; 20,000,000 shares authorized; 16,150, 973 shares issued at March 31, 2013 and 16,150,987 shares issued at December 31, 2012)	302,653	302,654
Retained earnings	447,829	441,605
Treasury stock (738,989 shares at March 31, 2013 and at December 31, 2012)	(76,375)	(76,375)
Accumulated other comprehensive (loss), net of taxes	(19,897)	(17,518)
Total stockholders' equity	654,210	650,366
Total liabilities and stockholders' equity	$ 6,747,155	$ 6,642,803