Fair Value Measurements, Fair Value Of Financial Instruments as Measured On a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024		Dec. 31, 2023		Mar. 31, 2023	Dec. 31, 2022
Assets: [Abstract]
Trading securities	$ 5,441,038		$ 5,193,505
Available for sale securities	12,653,088		12,286,681
Fair value option securities	19,805		20,671
Mortgage servicing rights	319,330		293,884		$ 299,803	$ 277,608
Derviative contracts, net of cash collateral, Assets, Fair value	263,493		410,304
Liabilities: [Abstract]
Derivative contracts, net of cash collateral, Liabilities, Fair Value	438,605		587,473
U.S. government securities [Member]
Assets: [Abstract]
Trading securities	426,825		10,959
Residential agency mortgage-backed securities [Member]
Assets: [Abstract]
Trading securities	4,898,485		5,105,137
Available for sale securities	7,816,688		6,834,720
Fair value option securities	19,805		20,671
Municipal securities [Member]
Assets: [Abstract]
Trading securities	67,120		37,413
Available for sale securities	304,826		502,833
U.S. Treasury [Member]
Assets: [Abstract]
Available for sale securities	920		925
Residential non-agency mortgage-backed securities [Member]
Assets: [Abstract]
Available for sale securities	846,805		799,877
Commercial agency mortgage-backed securities [Member]
Assets: [Abstract]
Available for sale securities	3,683,376		4,147,853
Other debt securities [Member]
Assets: [Abstract]
Trading securities	48,608		39,996
Available for sale securities	473		473
Fair Value, Recurring [Member]
Assets: [Abstract]
Trading securities	5,441,038		5,193,505
Available for sale securities	12,653,088		12,286,681
Residential mortgage loans held for sale	75,449	[1]	56,935	[2]
Mortgage servicing rights	319,330	[3]	293,884	[4]
Derviative contracts, net of cash collateral, Assets, Fair value	263,493	[5]	410,304	[6]
Liabilities: [Abstract]
Derivative contracts, net of cash collateral, Liabilities, Fair Value	438,605	[5]	587,473	[6]
Fair Value, Recurring [Member] | U.S. government securities [Member]
Assets: [Abstract]
Trading securities	426,825		10,959
Fair Value, Recurring [Member] | Residential agency mortgage-backed securities [Member]
Assets: [Abstract]
Trading securities	4,898,485		5,105,137
Available for sale securities	7,816,688		6,834,720
Fair value option securities	19,805		20,671
Fair Value, Recurring [Member] | Municipal securities [Member]
Assets: [Abstract]
Trading securities	67,120		37,413
Available for sale securities	304,826		502,833
Fair Value, Recurring [Member] | Other trading securities
Assets: [Abstract]
Trading securities	48,608		39,996
Fair Value, Recurring [Member] | U.S. Treasury [Member]
Assets: [Abstract]
Available for sale securities	920		925
Fair Value, Recurring [Member] | Residential non-agency mortgage-backed securities [Member]
Assets: [Abstract]
Available for sale securities	846,805		799,877
Fair Value, Recurring [Member] | Commercial agency mortgage-backed securities [Member]
Assets: [Abstract]
Available for sale securities	3,683,376		4,147,853
Fair Value, Recurring [Member] | Other debt securities [Member]
Assets: [Abstract]
Available for sale securities	473		473
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets: [Abstract]
Trading securities	370,062		9,017
Available for sale securities	920		925
Residential mortgage loans held for sale	0	[1]	0	[2]
Mortgage servicing rights	0	[3]	0	[4]
Derviative contracts, net of cash collateral, Assets, Fair value	10	[5]	0	[6]
Liabilities: [Abstract]
Derivative contracts, net of cash collateral, Liabilities, Fair Value	649	[5]	2,607	[6]
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. government securities [Member]
Assets: [Abstract]
Trading securities	370,062		9,017
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Residential agency mortgage-backed securities [Member]
Assets: [Abstract]
Trading securities	0		0
Available for sale securities	0		0
Fair value option securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal securities [Member]
Assets: [Abstract]
Trading securities	0		0
Available for sale securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other trading securities
Assets: [Abstract]
Trading securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Treasury [Member]
Assets: [Abstract]
Available for sale securities	920		925
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Residential non-agency mortgage-backed securities [Member]
Assets: [Abstract]
Available for sale securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial agency mortgage-backed securities [Member]
Assets: [Abstract]
Available for sale securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other debt securities [Member]
Assets: [Abstract]
Available for sale securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets: [Abstract]
Trading securities	5,070,976		5,184,488
Available for sale securities	12,651,695		12,285,283
Residential mortgage loans held for sale	68,285	[1]	49,749	[2]
Mortgage servicing rights	0	[3]	0	[4]
Derviative contracts, net of cash collateral, Assets, Fair value	263,483	[5]	410,304	[6]
Liabilities: [Abstract]
Derivative contracts, net of cash collateral, Liabilities, Fair Value	437,956	[5]	584,866	[6]
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. government securities [Member]
Assets: [Abstract]
Trading securities	56,763		1,942
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Residential agency mortgage-backed securities [Member]
Assets: [Abstract]
Trading securities	4,898,485		5,105,137
Available for sale securities	7,816,688		6,834,720
Fair value option securities	19,805		20,671
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal securities [Member]
Assets: [Abstract]
Trading securities	67,120		37,413
Available for sale securities	304,826		502,833
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other trading securities
Assets: [Abstract]
Trading securities	48,608		39,996
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Treasury [Member]
Assets: [Abstract]
Available for sale securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Residential non-agency mortgage-backed securities [Member]
Assets: [Abstract]
Available for sale securities	846,805		799,877
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial agency mortgage-backed securities [Member]
Assets: [Abstract]
Available for sale securities	3,683,376		4,147,853
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other debt securities [Member]
Assets: [Abstract]
Available for sale securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets: [Abstract]
Trading securities	0		0
Available for sale securities	473		473
Residential mortgage loans held for sale	7,164	[1]	7,186	[2]
Mortgage servicing rights	319,330	[3]	293,884	[4]
Derviative contracts, net of cash collateral, Assets, Fair value	$ 0	[5]	$ 0	[6]
Liquidity Discount on Mortgage Loans Qualifying for Sale to US Govt Agencies	77.97%		77.74%
Liabilities: [Abstract]
Derivative contracts, net of cash collateral, Liabilities, Fair Value	$ 0	[5]	$ 0	[6]
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. government securities [Member]
Assets: [Abstract]
Trading securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Residential agency mortgage-backed securities [Member]
Assets: [Abstract]
Trading securities	0		0
Available for sale securities	0		0
Fair value option securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal securities [Member]
Assets: [Abstract]
Trading securities	0		0
Available for sale securities			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other trading securities
Assets: [Abstract]
Trading securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Treasury [Member]
Assets: [Abstract]
Available for sale securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Residential non-agency mortgage-backed securities [Member]
Assets: [Abstract]
Available for sale securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial agency mortgage-backed securities [Member]
Assets: [Abstract]
Available for sale securities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other debt securities [Member]
Assets: [Abstract]
Available for sale securities	$ 473		$ 473

[1] Residential mortgage loans held for sale measured at fair value on a recurring basis using significant unobservable inputs (Level 3) consist of residential mortgage loans intended for sale to U.S. government agencies that fail to meet conforming standards and are valued at 77.97% of the unpaid principal balance.

[2] Residential mortgage loans held for sale measured at fair value on a recurring basis using significant unobservable inputs (Level 3) consist of residential mortgage loans intended for sale to U.S. government agencies that fail to meet conforming standards and are valued at 77.74% of the unpaid principal balance.

[3] A reconciliation of the beginning and ending fair value of mortgage servicing rights and disclosures of significant assumptions used to determine fair value are presented in Note 5, Mortgage Banking Activities.

[4] A reconciliation of the beginning and ending fair value of mortgage servicing rights and disclosures of significant assumptions used to determine fair value are presented in Note 5, Mortgage Banking Activities.

[5] See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in asset and liability positions that were valued based on quoted prices in active markets for identical instruments (Level 1) are primarily exchange-traded interest rate derivative contracts held for trading purposes.

[6] See Note 3 for detail of fair value of derivative contracts by contract type. Derivative contracts in asset and liability positions that were valued based on quoted prices in active markets for identical instruments (Level 1) are primarily exchange-traded interest rate derivative contracts held for trading purposes.