Intangible Assets (Summary Of Intangible Assets and Accumulated Amortization Included In The Consolidated Statements of Condition) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) branch	Dec. 31, 2017 USD ($)
Intangible Assets [Line Items]
Gross Carrying Amount	$ 240,637	$ 244,137
Accumulated Amortization	(66,222)	(59,748)
Net Carrying Value	$ 174,415	184,389
Number of branches divested | branch	2
Core deposit intangibles
Intangible Assets [Line Items]
Gross Carrying Amount	$ 157,150	160,650
Accumulated Amortization	(13,144)	(8,176)
Net Carrying Value	144,006	152,474
Customer relationships
Intangible Assets [Line Items]
Gross Carrying Amount	77,865	77,865
Accumulated Amortization	(52,018)	(50,777)
Net Carrying Value	25,847	27,088
Other
Intangible Assets [Line Items]
Gross Carrying Amount	5,622	5,622
Accumulated Amortization	(1,060)	(795)
Net Carrying Value	4,562	$ 4,827
State banking licenses
Intangible Assets [Line Items]
Net Carrying Value	$ 300