Investment Securities (Summary Of Available For Sale Investment Securities By Maturity Groupings) (Details) - USD ($)		Dec. 31, 2025	Dec. 31, 2024
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 9,742,278,000	$ 10,127,426,000
Debt Securities, Available-for-sale, Fair Value		9,095,513,000	9,136,853,000
U.S. Government And Federal Agency Obligations [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		3,257,561,000	2,594,130,000
Debt Securities, Available-for-sale, Fair Value		3,279,100,000	2,555,252,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost		389,021,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value		389,986,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost		1,779,346,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value		1,792,019,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost		982,623,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value		989,466,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost		106,571,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value		$ 107,629,000
Debt Securities, Available-for-Sale, Weighted Average Yield	[1]	3.61%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, Year One	[1]	3.85%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year One Through Five	[1]	3.46%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 5 Through 10	[1]	3.71%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 10	[1]	4.50%
US Government-sponsored Enterprise Debt Securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 54,951,000	55,425,000
Debt Securities, Available-for-sale, Fair Value		44,712,000	42,849,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost		4,306,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value		4,112,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost		30,824,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value		26,547,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost		19,821,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value		$ 14,053,000
Debt Securities, Available-for-Sale, Weighted Average Yield		2.37%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year One Through Five		2.94%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 5 Through 10		2.46%
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		$ 715,037,000	822,790,000
Debt Securities, Available-for-sale, Fair Value		664,733,000	742,891,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost		51,754,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value		51,339,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost		415,328,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value		397,576,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost		141,134,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value		126,470,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost		106,821,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value		$ 89,348,000
Debt Securities, Available-for-Sale, Weighted Average Yield		1.85%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, Year One		1.91%
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		2.14%
Agency mortgage-backed securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 3,786,811,000	4,195,182,000
Debt Securities, Available-for-sale, Fair Value		$ 3,223,105,000	3,444,891,000
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		$ 467,200,000	625,539,000
Debt Securities, Available-for-sale, Fair Value		$ 435,688,000	568,689,000
Debt Securities, Available-for-Sale, Weighted Average Yield		2.22%
Asset-backed Securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 1,269,503,000	1,595,797,000
Debt Securities, Available-for-sale, Fair Value		$ 1,262,045,000	1,557,015,000
Debt Securities, Available-for-Sale, Weighted Average Yield		3.78%
Total mortgage and asset-backed securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 5,523,514,000	6,416,518,000
Debt Securities, Available-for-sale, Fair Value		$ 4,920,838,000	5,570,595,000
Debt Securities, Available-for-Sale, Weighted Average Yield		2.50%
Other Debt Securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Amortized Cost		$ 191,215,000	238,563,000
Debt Securities, Available-for-sale, Fair Value		186,130,000	$ 225,266,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost		22,425,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value		22,278,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost		61,522,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value		57,611,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost		83,331,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value		82,357,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost		23,937,000
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value		$ 23,884,000
Debt Securities, Available-for-Sale, Weighted Average Yield		2.98%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, Year One		1.67%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year One Through Five		1.76%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 5 Through 10		4.08%
Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 10		3.48%

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