Investment Securities (Securities With Unrealized Losses And Length Of Impairment Period) (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	$ 1,051,875	$ 1,757,431
Unrealized Loss, Less than 12 months	10,305	27,884
Fair Value, Greater than 12 months	5,884,724	6,377,480
Unrealized Loss, Greater than 12 months	844,974	966,650
Debt Securities, Available-for-sale, Unrealized Loss Position	6,936,599	8,134,911
Unrealized Loss on AFS Debt Securities	855,279	994,534
U.S. government and federal agency obligations
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	764,764	1,492,875
Unrealized Loss, Less than 12 months	8,128	24,662
Fair Value, Greater than 12 months	289,771	353,129
Unrealized Loss, Greater than 12 months	8,437	17,197
Debt Securities, Available-for-sale, Unrealized Loss Position	1,054,535	1,846,004
Unrealized Loss on AFS Debt Securities	16,565	41,859
Government-sponsored enterprise obligations
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	0	0
Unrealized Loss, Less than 12 months	0	0
Fair Value, Greater than 12 months	44,056	42,848
Unrealized Loss, Greater than 12 months	10,985	12,576
Debt Securities, Available-for-sale, Unrealized Loss Position	44,056	42,848
Unrealized Loss on AFS Debt Securities	10,985	12,576
State and municipal obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	14,633	14,860
Unrealized Loss, Less than 12 months	368	230
Fair Value, Greater than 12 months	701,240	724,587
Unrealized Loss, Greater than 12 months	68,024	79,685
Debt Securities, Available-for-sale, Unrealized Loss Position	715,873	739,447
Unrealized Loss on AFS Debt Securities	68,392	79,915
Agency mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	2,920	3,882
Unrealized Loss, Less than 12 months	13	42
Fair Value, Greater than 12 months	3,382,090	3,409,405
Unrealized Loss, Greater than 12 months	668,998	750,664
Debt Securities, Available-for-sale, Unrealized Loss Position	3,385,010	3,413,287
Unrealized Loss on AFS Debt Securities	669,011	750,706
Non-Agency Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	38,677	10
Unrealized Loss, Less than 12 months	169	0
Fair Value, Greater than 12 months	512,713	564,637
Unrealized Loss, Greater than 12 months	48,799	56,986
Debt Securities, Available-for-sale, Unrealized Loss Position	551,390	564,647
Unrealized Loss on AFS Debt Securities	48,968	56,986
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	193,670	219,414
Unrealized Loss, Less than 12 months	1,499	2,371
Fair Value, Greater than 12 months	792,889	1,083,938
Unrealized Loss, Greater than 12 months	29,393	36,824
Debt Securities, Available-for-sale, Unrealized Loss Position	986,559	1,303,352
Unrealized Loss on AFS Debt Securities	30,892	39,195
Total Mortgage And Asset-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	235,267	223,306
Unrealized Loss, Less than 12 months	1,681	2,413
Fair Value, Greater than 12 months	4,687,692	5,057,980
Unrealized Loss, Greater than 12 months	747,190	844,474
Debt Securities, Available-for-sale, Unrealized Loss Position	4,922,959	5,281,286
Unrealized Loss on AFS Debt Securities	748,871	846,887
Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	37,211	26,390
Unrealized Loss, Less than 12 months	128	579
Fair Value, Greater than 12 months	161,965	198,936
Unrealized Loss, Greater than 12 months	10,338	12,718
Debt Securities, Available-for-sale, Unrealized Loss Position	199,176	225,326
Unrealized Loss on AFS Debt Securities	$ 10,466	$ 13,297