Segment Information (Summary Of Financial Information By Reportable Segment) (Details) - USD ($) $ in Thousands	3 Months Ended						6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Net interest income	$ 229,763				$ 212,503		$ 451,194	$ 431,038
(Recapture) provision for credit losses	(22,996)				87,085		(22,996)	205,170
Origination and sale	41,367				86,781		103,872	126,128
Servicing	9,120				8,533		18,207	17,413
Changes due to collection/realization of expected cash flows over time	(4,366)				(5,042)		(8,911)	(10,371)
Changes due to valuation inputs or assumptions	(1,678)				(6,395)		(3,692)	(31,753)
Gain on sale of debt securities, net	0				323		4	190
Gain (loss) on equity securities, net	4				240		(702)	1,054
Gain (loss) on swap derivatives, net	(4,481)				(823)		7,269	(15,129)
Non-interest income (excluding above items)	51,109				31,863		83,828	68,593
Noninterest Income	91,075				115,480		199,875	156,125
Goodwill impairment	0				0		0	1,784,936
Exit and disposal costs	4,728				548		5,928	1,072
Non-interest expense (excluding above items)	184,672				181,362		371,064	358,560
Allocated expenses, net	0				0		0	0
Total non-interest expense	189,400				181,910		376,992	2,144,568
Income (loss) before provision for income taxes	154,434				58,988		297,073	(1,762,575)
Provision for income taxes	38,291				6,062		73,193	36,446
Net income (loss)	116,143	$ 107,737	$ 150,730	$ 124,871	52,926	$ (1,851,947)	223,880	(1,799,021)
Total assets	30,284,965		29,235,175				30,284,965
Loans held for sale	429,052		766,225				429,052
Total loans and leases	22,143,739		21,779,367				22,143,739
Total deposits	26,153,553		24,622,201				26,153,553
Core Banking
Segment Reporting Information [Line Items]
Net interest income	226,915				208,245		444,489	424,351
(Recapture) provision for credit losses	(22,996)				87,085		(22,996)	205,170
Origination and sale	0				0		0	0
Servicing	0				0		0	0
Changes due to collection/realization of expected cash flows over time	0				0		0	0
Changes due to valuation inputs or assumptions	0				0		0	0
Gain on sale of debt securities, net	0				323		4	190
Gain (loss) on equity securities, net	4				240		(702)	1,054
Gain (loss) on swap derivatives, net	(4,481)				(823)		7,269	(15,129)
Non-interest income (excluding above items)	50,933				31,697		83,336	68,285
Noninterest Income	46,456				31,437		89,907	54,400
Goodwill impairment							0	1,784,936
Exit and disposal costs	4,728				548		5,928	1,072
Non-interest expense (excluding above items)	146,877				141,448		292,038	289,344
Allocated expenses, net	970				(1,963)		180	(5,016)
Total non-interest expense	152,575				140,033		298,146	2,070,336
Income (loss) before provision for income taxes	143,792				12,564		259,246	(1,796,755)
Provision for income taxes	35,630				(5,544)		63,736	27,901
Net income (loss)	108,162				18,108		195,510	(1,824,656)
Total assets	29,720,182		28,438,813				29,720,182
Loans held for sale	0		78,146				0
Total loans and leases	22,143,739		21,779,367				22,143,739
Total deposits	25,820,776		24,200,012				25,820,776
Mortgage Banking
Segment Reporting Information [Line Items]
Net interest income	2,848				4,258		6,705	6,687
(Recapture) provision for credit losses	0				0		0	0
Origination and sale	41,367				86,781		103,872	126,128
Servicing	9,120				8,533		18,207	17,413
Changes due to collection/realization of expected cash flows over time	(4,366)				(5,042)		(8,911)	(10,371)
Changes due to valuation inputs or assumptions	(1,678)				(6,395)		(3,692)	(31,753)
Gain on sale of debt securities, net	0				0		0	0
Gain (loss) on equity securities, net	0				0		0	0
Gain (loss) on swap derivatives, net	0				0		0	0
Non-interest income (excluding above items)	176				166		492	308
Noninterest Income	44,619				84,043		109,968	101,725
Goodwill impairment							0	0
Exit and disposal costs	0				0		0	0
Non-interest expense (excluding above items)	37,795				39,914		79,026	69,216
Allocated expenses, net	(970)				1,963		(180)	5,016
Total non-interest expense	36,825				41,877		78,846	74,232
Income (loss) before provision for income taxes	10,642				46,424		37,827	34,180
Provision for income taxes	2,661				11,606		9,457	8,545
Net income (loss)	7,981				$ 34,818		28,370	$ 25,635
Total assets	564,783		796,362				564,783
Loans held for sale	429,052		688,079				429,052
Total loans and leases	0		0				0
Total deposits	$ 332,777		$ 422,189				$ 332,777