Investment Securities (Summary Of Available For Sale Investment Securities By Maturity Groupings) (Details) - USD ($)		Dec. 31, 2024	Dec. 31, 2023
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 10,127,426,000	$ 10,904,765,000
Debt Securities, Available-for-sale, Fair Value		9,136,853,000	9,684,760,000
U.S. Government And Federal Agency Obligations [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		2,594,130,000	841,267,000
Debt Securities, Available-for-sale, Fair Value		2,555,252,000	816,514,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost		404,047,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value		404,675,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost		1,411,826,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value		1,396,419,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost		778,257,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value		$ 754,158,000
Debt Securities, Available-for-Sale, Weighted Average Yield	[1]	3.61%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, Year One	[1]	4.19%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year One Through Five	[1]	3.48%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 5 Through 10	[1]	3.55%
US Government-sponsored Enterprise Debt Securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 55,425,000	55,658,000
Debt Securities, Available-for-sale, Fair Value		42,849,000	43,962,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost		35,605,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value		29,574,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost		19,820,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value		$ 13,275,000
Debt Securities, Available-for-Sale, Weighted Average Yield		2.38%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 5 Through 10		2.52%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 10		2.12%
State and municipal obligations [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 822,790,000	1,346,633,000
Debt Securities, Available-for-sale, Fair Value		742,891,000	1,197,419,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost		92,129,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value		90,969,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost		386,856,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value		360,008,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost		226,723,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value		195,473,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost		117,082,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value		$ 96,441,000
Debt Securities, Available-for-Sale, Weighted Average Yield		1.80%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, Year One		1.45%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year One Through Five		1.79%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 5 Through 10		1.79%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 10		2.13%
Agency mortgage-backed securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 4,195,182,000	4,621,821,000
Debt Securities, Available-for-sale, Fair Value		$ 3,444,891,000	3,901,346,000
Debt Securities, Available-for-Sale, Weighted Average Yield		2.11%
Non-agency mortgage-backed securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 625,539,000	1,331,288,000
Debt Securities, Available-for-sale, Fair Value		$ 568,689,000	1,157,898,000
Debt Securities, Available-for-Sale, Weighted Average Yield		2.34%
Asset-backed Securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 1,595,797,000	2,200,712,000
Debt Securities, Available-for-sale, Fair Value		$ 1,557,015,000	2,107,485,000
Debt Securities, Available-for-Sale, Weighted Average Yield		3.18%
Total mortgage and asset-backed securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 6,416,518,000	8,153,821,000
Debt Securities, Available-for-sale, Fair Value		$ 5,570,595,000	7,166,729,000
Debt Securities, Available-for-Sale, Weighted Average Yield		2.40%
Other Debt Securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 238,563,000	507,386,000
Debt Securities, Available-for-sale, Fair Value		225,266,000	$ 460,136,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost		74,969,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value		74,439,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost		76,920,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value		72,033,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost		48,704,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value		42,179,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost		37,970,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value		$ 36,615,000
Debt Securities, Available-for-Sale, Weighted Average Yield		2.40%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, Year One		2.44%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year One Through Five		1.83%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 5 Through 10		2.00%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 10		3.99%

[1] Rate does not reflect inflation adjustment on inflation-protected securities