Segment Information (Summary Of Certain Operating Information For Reportable Segments) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net interest income	$ 190,778	$ 184,636	$ 175,270	$ 171,509	$ 167,206	$ 165,540	$ 156,892	$ 151,891	$ 722,193	$ 641,529	$ 598,575
Provision for credit losses	7,350	9,571	9,129	8,034	9,059	8,322	9,482	6,079	34,084	32,942	20,537
Non-interest income									325,430	271,597	215,240
Non-interest expense	180,371	176,615	170,969	153,730	166,829	159,974	154,297	147,318	681,685	628,419	546,847
Income tax expense	33,724	31,939	29,930	29,386	20,896	23,842	26,295	23,983	124,979	95,016	95,033
Net income	54,608	$ 53,115	$ 50,041	$ 49,111	35,512	$ 38,355	$ 43,831	$ 39,052	206,875	156,749	151,398
Total assets at end of year	25,668,553				22,909,348				25,668,553	22,909,348	19,998,840
Operating Segments
Segment Reporting Information [Line Items]
Net interest income									705,706	625,382	582,906
Provision for credit losses									34,084	32,942	20,537
Non-interest income									358,598	300,369	242,229
Non-interest expense									698,366	641,044	558,167
Income tax expense									124,979	95,016	95,033
Net income									206,875	156,749	151,398
Total assets at end of year	25,668,553				22,909,348				25,668,553	22,909,348	19,998,840
Operating Segments | Community Banking
Segment Reporting Information [Line Items]
Net interest income									588,847	523,112	484,523
Provision for credit losses									30,862	29,746	17,708
Non-interest income									230,414	191,248	136,307
Non-interest expense									556,798	522,199	444,416
Income tax expense									86,933	60,488	60,033
Net income									144,668	101,927	98,673
Total assets at end of year	21,172,080				19,244,111				21,172,080	19,244,111	16,713,329
Operating Segments | Specialty Finance
Segment Reporting Information [Line Items]
Net interest income									98,248	85,258	82,415
Provision for credit losses									3,222	3,196	2,829
Non-interest income									49,706	33,625	32,534
Non-interest expense									66,460	47,245	44,320
Income tax expense									29,512	26,352	27,167
Net income									48,760	42,090	40,633
Total assets at end of year	3,884,373				3,116,348				3,884,373	3,116,348	2,765,671
Operating Segments | Wealth Management
Segment Reporting Information [Line Items]
Net interest income									18,611	17,012	15,968
Provision for credit losses									0	0	0
Non-interest income									78,478	75,496	73,388
Non-interest expense									75,108	71,600	69,431
Income tax expense									8,534	8,176	7,833
Net income									13,447	12,732	12,092
Total assets at end of year	612,100				548,889				612,100	548,889	519,840
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net interest income									16,487	16,147	15,669
Provision for credit losses									0	0	0
Non-interest income									(33,168)	(28,772)	(26,989)
Non-interest expense									(16,681)	(12,625)	(11,320)
Income tax expense									0	0	0
Net income									0	0	0
Total assets at end of year	$ 0				$ 0				$ 0	$ 0	$ 0