Segment Information (Summary Of Financial Information By Reportable Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net interest income	$ 919,647	$ 882,519	$ 920,634
(Recapture) provision for credit losses	(42,651)	204,861	72,515
Origination and sale	157,789	308,219	104,394
Servicing	36,836	35,706	42,199
Changes due to collection/realization of expected cash flows over time	(18,903)	(19,680)	(25,408)
Changes due to valuation inputs or assumptions	11,089	(53,423)	(19,375)
Gain (loss) on sale of debt securities, net	8	190	(7,184)
(Loss) gain on equity securities, net	(1,511)	769	83,475
Gain on swap derivatives, net	8,395	(9,409)	(6,038)
Change in fair value of certain loans held for investment	3,032
Non-interest income (excluding above items)	159,583	149,637	167,761
Noninterest Income	356,318	412,009	339,824
Merger related expenses	15,183
Goodwill impairment	0	1,784,936	0
Exit and disposal costs	12,763	2,589	6,797
Non-interest expense (excluding above items)	732,510	758,562	712,243
Allocated expense, net	0	0	0
Total non-interest expense	760,456	2,546,087	719,040
Income before income taxes	558,160	(1,456,420)	468,903
Provision for income taxes	137,860	67,000	114,808
Net Income (Loss) Attributable to Parent, Total	420,300	(1,523,420)	354,095
Total assets	30,640,936	29,235,175	28,846,809
Loans held for sale	353,105	766,225	513,431
Total loans and leases	22,553,180	21,779,367	21,195,684
Total deposits	26,594,685	24,622,201	22,481,504
Core Banking
Segment Reporting Information [Line Items]
Net interest income	908,087	866,996	913,097
(Recapture) provision for credit losses	(42,651)	204,861	72,515
Origination and sale	0	0	0
Servicing	0	0	0
Changes due to collection/realization of expected cash flows over time	0	0	0
Changes due to valuation inputs or assumptions	0	0	0
Gain (loss) on sale of debt securities, net	8	190	(7,184)
(Loss) gain on equity securities, net	(1,511)	769	83,475
Gain on swap derivatives, net	8,395	(9,409)	(6,038)
Change in fair value of certain loans held for investment	3,032
Non-interest income (excluding above items)	158,725	148,884	167,325
Noninterest Income	168,649	140,434	237,578
Merger related expenses	15,183
Goodwill impairment		1,784,936
Exit and disposal costs	12,763	2,589	6,797
Non-interest expense (excluding above items)	589,556	609,497	606,545
Allocated expense, net	8,174	(11,557)	(10,508)
Total non-interest expense	625,676	2,385,465	602,834
Income before income taxes	493,711	(1,582,896)	475,326
Provision for income taxes	121,748	35,381	116,414
Net Income (Loss) Attributable to Parent, Total	371,963	(1,618,277)	358,912
Total assets	30,155,058	28,438,813	28,214,661
Loans held for sale	0	78,146	0
Total loans and leases	22,553,180	21,779,367	21,195,684
Total deposits	26,370,568	24,200,012	22,212,584
Mortgage Banking
Segment Reporting Information [Line Items]
Net interest income	11,560	15,523	7,537
(Recapture) provision for credit losses	0	0	0
Origination and sale	157,789	308,219	104,394
Servicing	36,836	35,706	42,199
Changes due to collection/realization of expected cash flows over time	(18,903)	(19,680)	(25,408)
Changes due to valuation inputs or assumptions	11,089	(53,423)	(19,375)
Gain (loss) on sale of debt securities, net	0	0	0
(Loss) gain on equity securities, net	0	0	0
Gain on swap derivatives, net	0	0	0
Change in fair value of certain loans held for investment	0
Non-interest income (excluding above items)	858	753	436
Noninterest Income	187,669	271,575	102,246
Merger related expenses	0
Goodwill impairment		0
Exit and disposal costs	0	0	0
Non-interest expense (excluding above items)	142,954	149,065	105,698
Allocated expense, net	(8,174)	11,557	10,508
Total non-interest expense	134,780	160,622	116,206
Income before income taxes	64,449	126,476	(6,423)
Provision for income taxes	16,112	31,619	(1,606)
Net Income (Loss) Attributable to Parent, Total	48,337	94,857	(4,817)
Total assets	485,878	796,362	632,148
Loans held for sale	353,105	688,079	513,431
Total loans and leases	0	0	0
Total deposits	$ 224,117	$ 422,189	$ 268,920