Goodwill and Other Intangible Assets (Goodwill And Other Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Goodwill, Total, Beginning Balance	$ 1,787,793
Goodwill, Impairment Loss	(142)	$ 0	$ 0
Goodwill, Total, Ending Balance	1,787,651	1,787,793
Finite-lived Intangible Assets [Roll Forward]
Other Intangible Assets, Amortization	(8,622)	(11,225)	(10,207)
Other Intangible Assets, Net, Ending Balance	36,886
Community Banking
Goodwill [Roll Forward]
Goodwill, Gross, Beginning Balance	1,900,727	1,899,159	877,239
Goodwill, Impaired, Accumulated Impairment Loss, Beginning Balance	(112,934)	(112,934)	(112,934)
Goodwill, Total, Beginning Balance	1,787,793	1,786,225	764,305
Goodwill, Net Additions		1,568	1,021,920
Goodwill, Reductions	0
Goodwill, Impairment Loss	(142)
Goodwill, Gross, Ending Balance	1,900,727	1,900,727	1,899,159
Goodwill, Impaired, Accumulated Impairment Loss, Ending Balance	(113,076)	(112,934)	(112,934)
Goodwill, Total, Ending Balance	1,787,651	1,787,793	1,786,225
Other Intagible Assets
Finite-lived Intangible Assets [Roll Forward]
Other Intangible Assets, Gross, Beginning Balance	113,471	113,471	58,909
Other Intangible Assets, Accumulated Amortization, Beginning Balance	(67,963)	(56,738)	(46,531)
Other Intangible Assets, Net, Beginning Balance	45,508	56,733	12,378
Other intangible assets, Net additions			54,562
Other Intangible Assets, Amortization	(8,622)	(11,225)	(10,207)
Other Intangible Assets, Gross, Ending Balance	113,471	113,471	113,471
Other Intangible Assets, Accumulated Amortization, Ending Balance	(76,585)	(67,963)	(56,738)
Other Intangible Assets, Net, Ending Balance	$ 36,886	$ 45,508	$ 56,733