Segments Segments (Segment Balance Sheet Data) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Average Assets	$ 22,672,923	$ 21,873,984
Loans, including held for sale	11,260,233	10,316,142
Goodwill and other intangible assets	147,265	136,011
Deposits	18,795,676	18,061,151
Consumer Segment [Member]
Segment Reporting Information [Line Items]
Average Assets	2,806,028	2,674,136
Loans, including held for sale	2,718,634	2,589,179
Goodwill and other intangible assets	76,786	73,340
Deposits	9,537,686	9,317,525
Commercial Segment [Member]
Segment Reporting Information [Line Items]
Average Assets	6,966,520	6,321,153
Loans, including held for sale	6,783,471	6,124,902
Goodwill and other intangible assets	69,733	61,925
Deposits	7,288,884	6,809,265
Wealth Segment [Member]
Segment Reporting Information [Line Items]
Average Assets	931,397	855,721
Loans, including held for sale	922,120	845,918
Goodwill and other intangible assets	746	746
Deposits	1,911,391	1,885,807
Segment Totals [Member]
Segment Reporting Information [Line Items]
Average Assets	10,703,945	9,851,010
Loans, including held for sale	10,424,225	9,559,999
Goodwill and other intangible assets	147,265	136,011
Deposits	18,737,961	18,012,597
Other/Elimination [Member]
Segment Reporting Information [Line Items]
Average Assets	11,968,978	12,022,974
Loans, including held for sale	836,008	756,143
Goodwill and other intangible assets	0	0
Deposits	$ 57,715	$ 48,554