Segment Information (Summary Of Financial Information By Reportable Segment) (Details) - USD ($) $ in Thousands	3 Months Ended							9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Net interest income	$ 235,074				$ 216,574			$ 686,268	$ 647,612
(Recapture) provision for credit losses	(18,919)				(338)			(41,915)	204,832
Origination and sale	30,293				98,703			134,165	224,831
Servicing	9,172				8,796			27,379	26,209
Changes due to collection/realization of expected cash flows over time	(4,681)				(4,878)			(13,592)	(15,249)
Changes due to valuation inputs or assumptions	(634)				(12,244)			(4,326)	(43,997)
Gain on sale of debt securities, net	0				0			4	190
(Loss) gain on equity securities, net	(343)				(112)			(1,045)	942
Gain (loss) on swap derivatives, net	1,429				1,765			8,698	(13,364)
Non-interest income (excluding above items)	38,469				39,894			122,297	108,487
Noninterest Income	73,705				131,924			273,580	288,049
Goodwill impairment	0				0			0	1,784,936
Exit and disposal costs	3,813				792			9,741	1,864
Non-interest expense (excluding above items)	179,940				189,415			551,004	547,975
Allocated expenses, net	0				0			0	0
Total non-interest expense	183,753				190,207			560,745	2,334,775
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	143,945				158,629			441,018	(1,603,946)
Provision for income taxes	35,879				33,758			109,072	70,204
Net income (loss)	108,066	$ 116,143	$ 107,737	$ 150,730	124,871	$ 52,926	$ (1,851,947)	331,946	(1,674,150)
Total assets	30,891,479			29,235,175				30,891,479
Loans held for sale	352,466			766,225				352,466
Total loans and leases	21,969,940			21,779,367				21,969,940
Total deposits	26,908,397			24,622,201				26,908,397
Core Banking
Segment Reporting Information [Line Items]
Net interest income	232,348				212,215			676,837	636,566
(Recapture) provision for credit losses	(18,919)				(338)			(41,915)	204,832
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								4	190
(Loss) gain on equity securities, net	(343)				(112)			(1,045)	942
Gain (loss) on swap derivatives, net	1,429				1,765			8,698	(13,364)
Non-interest income (excluding above items)	38,281				39,678			121,617	107,963
Noninterest Income	39,367				41,331			129,274	95,731
Goodwill impairment								0	1,784,936
Exit and disposal costs	3,813				792			9,741	1,864
Non-interest expense (excluding above items)	146,931				148,519			438,969	437,863
Allocated expenses, net	3,680				(2,976)			3,860	(7,992)
Total non-interest expense	154,424				146,335			452,570	2,216,671
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	136,210				107,549			395,456	(1,689,206)
Provision for income taxes	33,945				20,988			97,681	48,889
Net income (loss)	102,265				86,561			297,775	(1,738,095)
Total assets	30,419,108			28,438,813				30,419,108
Loans held for sale	0			78,146				0
Total loans and leases	21,969,940			21,779,367				21,969,940
Total deposits	26,510,938			24,200,012				26,510,938
Mortgage Banking
Segment Reporting Information [Line Items]
Net interest income	2,726				4,359			9,431	11,046
(Recapture) provision for credit losses	0				0			0	0
Origination and sale	30,293				98,703			134,165	224,831
Servicing	9,172				8,796			27,379	26,209
Changes due to collection/realization of expected cash flows over time	(4,681)				(4,878)			(13,592)	(15,249)
Changes due to valuation inputs or assumptions	(634)				(12,244)			(4,326)	(43,997)
Gain on sale of debt securities, net								0	0
(Loss) gain on equity securities, net	0				0			0	0
Gain (loss) on swap derivatives, net	0				0			0	0
Non-interest income (excluding above items)	188				216			680	524
Noninterest Income	34,338				90,593			144,306	192,318
Goodwill impairment								0	0
Exit and disposal costs	0				0			0	0
Non-interest expense (excluding above items)	33,009				40,896			112,035	110,112
Allocated expenses, net	(3,680)				2,976			(3,860)	7,992
Total non-interest expense	29,329				43,872			108,175	118,104
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	7,735				51,080			45,562	85,260
Provision for income taxes	1,934				12,770			11,391	21,315
Net income (loss)	5,801				$ 38,310			34,171	$ 63,945
Total assets	472,371			796,362				472,371
Loans held for sale	352,466			688,079				352,466
Total loans and leases	0			0				0
Total deposits	$ 397,459			$ 422,189				$ 397,459