Goodwill and Other Intangible Assets (Goodwill And Other Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Roll Forward]
Goodwill, Total, Beginning Balance	$ 1,786,225
Goodwill, Total, Ending Balance	1,787,793	$ 1,786,225
Finite-lived Intangible Assets [Roll Forward]
Other Intangible Assets, Amortization	(11,225)	(10,207)	$ (4,781)
Other Intangible Assets, Net, Ending Balance	45,508
Community Banking [Member]
Goodwill [Roll Forward]
Goodwill, Gross, Beginning Balance	1,899,159	877,239	781,106
Goodwill, Impaired, Accumulated Impairment Loss, Beginning Balance	(112,934)	(112,934)	(112,934)
Goodwill, Total, Beginning Balance	1,786,225	764,305	668,172
Goodwill, Net additions	1,568	1,021,920	96,777
Goodwill, Reductions	0	0	(644)
Goodwill, Gross, Ending Balance	1,900,727	1,899,159	877,239
Goodwill, Impaired, Accumulated Impairment Loss, Ending Balance	(112,934)	(112,934)	(112,934)
Goodwill, Total, Ending Balance	1,787,793	1,786,225	764,305
Other Intagible Assets [Member]
Finite-lived Intangible Assets [Roll Forward]
Other Intangible Assets, Gross, Beginning Balance	113,471	58,909	58,909
Other Intangible Assets, Accumulated Amortization, Beginning Balance	(56,738)	(46,531)	(41,750)
Other Intangible Assets, Net, Beginning Balance	56,733	12,378	17,159
Other Intangible Assets, Net additions	0	54,562	0
Other Intangible Assets, Amortization	(11,225)	(10,207)	(4,781)
Other Intangible Assets, Gross, Ending Balance	113,471	113,471	58,909
Other Intangible Assets, Accumulated Amortization, Ending Balance	(67,963)	(56,738)	(46,531)
Other Intangible Assets, Net, Ending Balance	$ 45,508	$ 56,733	$ 12,378