Income Taxes Deferred Tax Assetss And Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Allowance for credit losses	$ 62,726	$ 62,846
Postretirement and defined benefit plans	12,659	13,070
State loss carryforwards	9,820	11,170
Other accrued expenses	12,017	11,839
Other-than-temporary impairment of investments	5,187	5,501
Other accrued expenses	9,520	7,142
Unrealized holding losses on securities available for sale	12,260	3,250
Other	8,500	10,165
Total gross deferred tax assets	132,689	124,983
Deferred Tax Liabilities, Gross [Abstract]
Mortgage servicing rights	13,369	14,582
Direct leasing	27,663	20,309
Acquisition premiums/discounts	9,167	8,897
Premises and equipment	5,625	5,955
Intangible assets	1,810	1,614
Other	12,530	9,593
Total gross deferred tax liabilities	70,164	60,950
Net deferred tax asset, before valuation allowance	62,525	64,033
Valuation allowance	(8,950)	(8,359)
Net deferred tax asset	53,575	55,674
State and local operating loss carryforwards	391,000	$ 424,000
Capital loss carryforwards	2,500
Deferred tax assets other than temporary impairment losses investment securities	$ 5,000