Fair Value Measurements (Summary Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands		Jun. 30, 2024	Dec. 31, 2023
Fair Value Measurements [Line Items]
Residential mortgage loans held for sale		$ 2,186	$ 1,585
U.S. government and federal agency obligations		1,637,827	816,514
Government-sponsored enterprise obligations		43,139	43,962
State and municipal obligations		775,983	1,197,419
Agency mortgage-backed securities		3,630,296	3,901,346
Non-agency mortgage-backed securities		646,357	1,157,898
Asset-backed securities		1,583,747	2,107,485
Other debt securities		216,922	460,136
Trading debt securities		45,499	28,830
Equity securities		47,804	5,723
Private equity investments		178,321	176,667
Derivative Asset	[1]	86,709	116,876
Assets held in trust for deferred compensation plan		21,550	20,538
Total assets		8,916,340	10,034,979
Derivative Liabilities	[1]	36,915	37,899
Liabilities held in trust for deferred compensation plan		21,550	20,538
Total Liabilities		58,465	58,437
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Measurements [Line Items]
Residential mortgage loans held for sale		0	0
U.S. government and federal agency obligations		1,637,827	816,514
Government-sponsored enterprise obligations		0	0
State and municipal obligations		0	0
Agency mortgage-backed securities		0	0
Non-agency mortgage-backed securities		0	0
Asset-backed securities		0	0
Other debt securities		0	0
Trading debt securities		0	0
Equity securities		47,804	5,723
Private equity investments		0	0
Derivative Asset	[1]	0	0
Assets held in trust for deferred compensation plan		21,550	20,538
Total assets		1,707,181	842,775
Derivative Liabilities	[1]	0	0
Liabilities held in trust for deferred compensation plan		21,550	20,538
Total Liabilities		21,550	20,538
Significant Other Observable Inputs (Level 2)
Fair Value Measurements [Line Items]
Residential mortgage loans held for sale		2,186	1,585
U.S. government and federal agency obligations		0	0
Government-sponsored enterprise obligations		43,139	43,962
State and municipal obligations		775,030	1,196,472
Agency mortgage-backed securities		3,630,296	3,901,346
Non-agency mortgage-backed securities		646,357	1,157,898
Asset-backed securities		1,583,747	2,107,485
Other debt securities		216,922	460,136
Trading debt securities		45,499	28,830
Equity securities		0	0
Private equity investments		0	0
Derivative Asset	[1]	86,511	116,710
Assets held in trust for deferred compensation plan		0	0
Total assets		7,029,687	9,014,424
Derivative Liabilities	[1]	36,832	37,704
Liabilities held in trust for deferred compensation plan		0	0
Total Liabilities		36,832	37,704
Significant Unobservable Inputs (Level 3)
Fair Value Measurements [Line Items]
Residential mortgage loans held for sale		0	0
U.S. government and federal agency obligations		0	0
Government-sponsored enterprise obligations		0	0
State and municipal obligations		953	947
Agency mortgage-backed securities		0	0
Non-agency mortgage-backed securities		0	0
Asset-backed securities		0	0
Other debt securities		0	0
Trading debt securities		0	0
Equity securities		0	0
Private equity investments		178,321	176,667
Derivative Asset	[1]	198	166
Assets held in trust for deferred compensation plan		0	0
Total assets		179,472	177,780
Derivative Liabilities	[1]	83	195
Liabilities held in trust for deferred compensation plan		0	0
Total Liabilities		$ 83	$ 195

[1] * The fair value of each class of derivative is shown in Note 11.