Fair Value Measurement (Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other investment securities	$ 73,638		$ 72,959
Investment securities available for sale	8,503,986		3,196,166
Loans held for sale	60,313		71,647
Loans Receivable, Fair Value Disclosure	257,911		285,581
Residential mortgage servicing rights, at fair value	117,640	$ 172,929	185,017	$ 196,177	$ 179,558	$ 123,615
Derivative Asset	769		15,444
Total assets measured at fair value	9,014,257		3,826,814
Junior subordinated debentures, at fair value	331,545		323,639
Derivative Liability	403,821		271,205
Total liabilities measured at fair value	735,366		594,844
Foreign currency derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	328		225
Derivative Liability	236		185
Investments in mutual funds and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other investment securities	60,705		61,593
Equity securities held in rabbi trusts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other investment securities	12,933		11,366
U.S. Treasury and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,436,552		936,174
Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	998,798		269,800
Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	6,068,636		1,990,192
Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset			50
Derivative Liability	427		18
Interest rate futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	1,630		392
Interest rate forward sales commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	441		512
Derivative Liability	13		601
Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset			14,657
Derivative Liability	401,515		270,009
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0		0
Loans Receivable, Fair Value Disclosure	0		0
Residential mortgage servicing rights, at fair value	0		0
Total assets measured at fair value	421,395		281,475
Junior subordinated debentures, at fair value	0		0
Total liabilities measured at fair value	0		0
Level 1 | Foreign currency derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0		0
Derivative Liability	0		0
Level 1 | Investments in mutual funds and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other investment securities	42,246		44,256
Level 1 | Equity securities held in rabbi trusts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other investment securities	12,933		11,366
Level 1 | U.S. Treasury and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	366,216		225,853
Level 1 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0		0
Level 1 | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0		0
Level 1 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset			0
Derivative Liability	0		0
Level 1 | Interest rate futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	0		0
Level 1 | Interest rate forward sales commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0		0
Derivative Liability	0		0
Level 1 | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset			0
Derivative Liability	0		0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	60,313		71,647
Loans Receivable, Fair Value Disclosure	257,911		285,581
Residential mortgage servicing rights, at fair value	0		0
Total assets measured at fair value	8,475,222		3,360,272
Junior subordinated debentures, at fair value	0		0
Total liabilities measured at fair value	403,394		271,187
Level 2 | Foreign currency derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	328		225
Derivative Liability	236		185
Level 2 | Investments in mutual funds and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other investment securities	18,459		17,337
Level 2 | Equity securities held in rabbi trusts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other investment securities	0		0
Level 2 | U.S. Treasury and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,070,336		710,321
Level 2 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	998,798		269,800
Level 2 | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	6,068,636		1,990,192
Level 2 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset			0
Derivative Liability	0		0
Level 2 | Interest rate futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	1,630		392
Level 2 | Interest rate forward sales commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	441		512
Derivative Liability	13		601
Level 2 | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset			14,657
Derivative Liability	401,515		270,009
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0		0
Loans Receivable, Fair Value Disclosure	0		0
Residential mortgage servicing rights, at fair value	117,640		185,017
Total assets measured at fair value	117,640		185,067
Junior subordinated debentures, at fair value	331,545		323,639
Total liabilities measured at fair value	331,972		323,657
Level 3 | Foreign currency derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0		0
Derivative Liability	0		0
Level 3 | Investments in mutual funds and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other investment securities	0		0
Level 3 | Equity securities held in rabbi trusts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other investment securities	0		0
Level 3 | U.S. Treasury and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0		0
Level 3 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0		0
Level 3 | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0		0
Level 3 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset			50
Derivative Liability	427		18
Level 3 | Interest rate futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	0		0
Level 3 | Interest rate forward sales commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0		0
Derivative Liability	0		0
Level 3 | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset			0
Derivative Liability	$ 0		$ 0