Segments Segments (Segment Balance Sheet Data) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Average Assets	$ 25,213,525	$ 24,666,235
Average Loans, including held for sale	14,243,214	13,945,572
Average Goodwill and other intangible assets	147,910	147,108
Average Deposits	19,909,891	20,131,252
Consumer Segment [Member]
Segment Reporting Information [Line Items]
Average Assets	2,375,326	2,481,060
Average Loans, including held for sale	2,239,100	2,346,166
Average Goodwill and other intangible assets	79,055	78,062
Average Deposits	10,236,257	10,210,502
Commercial Segment [Member]
Segment Reporting Information [Line Items]
Average Assets	9,486,074	9,115,738
Average Loans, including held for sale	9,250,645	8,939,696
Average Goodwill and other intangible assets	68,109	68,300
Average Deposits	7,848,367	8,029,248
Wealth Segment [Member]
Segment Reporting Information [Line Items]
Average Assets	1,288,806	1,243,806
Average Loans, including held for sale	1,276,839	1,233,780
Average Goodwill and other intangible assets	746	746
Average Deposits	1,832,418	1,871,596
Segment Totals [Member]
Segment Reporting Information [Line Items]
Average Assets	13,150,206	12,840,604
Average Loans, including held for sale	12,766,584	12,519,642
Average Goodwill and other intangible assets	147,910	147,108
Average Deposits	19,917,042	20,111,346
Other/Elimination [Member]
Segment Reporting Information [Line Items]
Average Assets	12,063,319	11,825,631
Average Loans, including held for sale	1,476,630	1,425,930
Average Goodwill and other intangible assets	0	0
Average Deposits	$ (7,151)	$ 19,906