Fair Value Measurements, Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2023		Mar. 31, 2023	Dec. 31, 2022		Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	$ 5,442,364			$ 4,464,161
Debt Securities, Held-to-maturity, gross	2,567,448			2,739,241
Investment securities, Allowance for Credit Loss	(465)	[1]		(558)	[2]
Investment Securities, Amortized Cost, After Allowance for Credit Loss	2,566,983			2,738,683
Available for sale securities	11,938,523			11,493,860
Fair value option securities	212,321			296,590
Residential mortgage loans held for sale	94,820			75,272
Loans	23,237,659			22,557,150
Allowance for loan losses	(262,714)			(235,704)
Loans, net of allowance	22,974,945			22,321,446
Mortgage servicing rights	304,722		$ 299,803	277,608		$ 270,312	$ 209,563	$ 163,198
Derviative contracts, net of cash collateral, Assets, Fair value	353,037			880,343
Time deposits	2,706,377			1,461,842
Subordinated debentures	131,154			131,205
Derivative contracts, net of cash collateral, Liabilities, Fair Value	550,653			554,900
Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	14,534,516			14,212,499
Allowance for loan losses	(143,269)			(131,586)
Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,970,801			4,606,777
Allowance for loan losses	(76,347)			(57,648)
Loans to individuals [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,732,342			3,737,874
Allowance for loan losses	(43,098)			(46,470)
U.S. government securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	46,994			9,823
Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	5,334,372			4,406,848
Debt Securities, Held-to-maturity, gross	2,397,098			2,538,565
Available for sale securities	6,114,202			5,814,496
Fair value option securities	212,321			296,590
Municipal securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	49,595			21,484
Debt Securities, Held-to-maturity, gross	136,803			170,629
Available for sale securities	491,715			624,500
U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	901			898
Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	699,178			577,576
Commercial agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	17,259			17,259
Available for sale securities	4,632,054			4,475,917
Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	11,403			26,006
Debt Securities, Held-to-maturity, gross	16,288			12,788
Available for sale securities	473			473
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	875,714			943,810
Interest-bearing cash and cash equivalents	571,616			457,906
Trading securities	5,442,364			4,464,161
Debt Securities, Held-to-maturity, gross	2,374,536			2,514,245
Investment securities, Allowance for Credit Loss	(465)			(558)
Investment Securities, Amortized Cost, After Allowance for Credit Loss	2,374,071			2,513,687
Available for sale securities	11,938,523			11,493,860
Residential mortgage loans held for sale	94,820			75,272
Loans	23,237,659			22,557,150
Allowance for loan losses	(262,714)			(235,704)
Loans, net of allowance	22,974,945			22,321,446
Mortgage servicing rights	304,722			277,608
Derviative contracts, net of cash collateral, Assets, Fair value	353,037			880,343
Deposits with no stated maturity	30,588,466			33,018,863
Time deposits	2,706,377			1,461,842
Other borrowed funds	9,223,920			7,007,285
Subordinated debentures	131,154			131,205
Derivative contracts, net of cash collateral, Liabilities, Fair Value	550,653			554,900
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	14,534,516			14,212,499
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,970,801			4,606,777
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Loans to individuals [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,732,342			3,737,874
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. government securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	46,994			9,823
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	5,334,372			4,406,848
Debt Securities, Held-to-maturity, gross	2,205,685			2,315,219
Available for sale securities	6,114,202			5,814,496
Fair value option securities	212,321			296,590
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Municipal securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	49,595			21,484
Debt Securities, Held-to-maturity, gross	136,803			170,629
Available for sale securities	491,715			624,500
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	11,403			26,006
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	901			898
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	699,178			577,576
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	15,760			15,609
Available for sale securities	4,632,054			4,475,917
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	16,288			12,788
Available for sale securities	473			473
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	875,714			943,810
Interest-bearing cash and cash equivalents	571,616			457,906
Trading securities	5,442,364			4,464,161
Debt Securities, Held-to-maturity, gross	2,185,384			2,346,768
Investment securities, Allowance for Credit Loss	0			0
Investment Securities, Amortized Cost, After Allowance for Credit Loss	2,185,384			2,346,768
Available for sale securities	11,938,523			11,493,860
Residential mortgage loans held for sale	94,820			75,272
Loans	22,846,124			21,891,223
Allowance for loan losses	0			0
Loans, net of allowance	22,846,124			21,891,223
Mortgage servicing rights	304,722			277,608
Derviative contracts, net of cash collateral, Assets, Fair value	353,037			880,343
Deposits with no stated maturity	30,588,466			33,018,863
Time deposits	2,672,789			1,431,245
Other borrowed funds	9,221,872			7,005,305
Subordinated debentures	112,501			121,497
Derivative contracts, net of cash collateral, Liabilities, Fair Value	550,653			554,900
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	14,428,246			13,905,765
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,839,799			4,454,048
Estimate of Fair Value, Fair Value Disclosure [Member] | Loans to individuals [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,578,079			3,531,410
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	46,994			9,823
Estimate of Fair Value, Fair Value Disclosure [Member] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	5,334,372			4,406,848
Debt Securities, Held-to-maturity, gross	2,014,427			2,143,360
Available for sale securities	6,114,202			5,814,496
Fair value option securities	212,321			296,590
Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	49,595			21,484
Debt Securities, Held-to-maturity, gross	141,587			176,621
Available for sale securities	491,715			624,500
Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	11,403			26,006
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	901			898
Estimate of Fair Value, Fair Value Disclosure [Member] | Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	699,178			577,576
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	14,636			14,588
Available for sale securities	4,632,054			4,475,917
Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	14,734			12,199
Available for sale securities	473			473
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	875,714			943,810
Interest-bearing cash and cash equivalents	571,616			457,906
Trading securities	4,963			4,970
Debt Securities, Held-to-maturity, gross	0			0
Investment securities, Allowance for Credit Loss	0			0
Investment Securities, Amortized Cost, After Allowance for Credit Loss	0			0
Available for sale securities	901			898
Residential mortgage loans held for sale	0			0
Loans	0			0
Allowance for loan losses	0			0
Loans, net of allowance	0			0
Mortgage servicing rights	0			0
Derviative contracts, net of cash collateral, Assets, Fair value	2,506			2,110
Deposits with no stated maturity	0			0
Time deposits	0			0
Other borrowed funds	0			0
Subordinated debentures	0			0
Derivative contracts, net of cash collateral, Liabilities, Fair Value	4			16
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0			0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0			0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Loans to individuals [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0			0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	4,963			4,970
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0			0
Debt Securities, Held-to-maturity, gross	0			0
Available for sale securities	0			0
Fair value option securities	0			0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0			0
Debt Securities, Held-to-maturity, gross	0			0
Available for sale securities	0			0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0			0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	901			898
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0			0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	0			0
Available for sale securities	0			0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	0			0
Available for sale securities	0			0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0			0
Interest-bearing cash and cash equivalents	0			0
Trading securities	5,437,401			4,459,191
Debt Securities, Held-to-maturity, gross	2,061,364			2,208,253
Investment securities, Allowance for Credit Loss	0			0
Investment Securities, Amortized Cost, After Allowance for Credit Loss	2,061,364			2,208,253
Available for sale securities	11,937,149			11,492,489
Residential mortgage loans held for sale	87,572			68,054
Loans	0			0
Allowance for loan losses	0			0
Loans, net of allowance	0			0
Mortgage servicing rights	0			0
Derviative contracts, net of cash collateral, Assets, Fair value	350,531			878,233
Deposits with no stated maturity	0			0
Time deposits	0			0
Other borrowed funds	0			0
Subordinated debentures	112,501			121,497
Derivative contracts, net of cash collateral, Liabilities, Fair Value	550,649			554,884
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0			0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0			0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Loans to individuals [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0			0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	42,031			4,853
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	5,334,372			4,406,848
Debt Securities, Held-to-maturity, gross	2,014,427			2,143,360
Available for sale securities	6,114,202			5,814,496
Fair value option securities	212,321			296,590
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	49,595			21,484
Debt Securities, Held-to-maturity, gross	17,567			38,106
Available for sale securities	491,715			624,500
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	11,403			26,006
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0			0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	699,178			577,576
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	14,636			14,588
Available for sale securities	4,632,054			4,475,917
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	14,734			12,199
Available for sale securities	0			0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0			0
Interest-bearing cash and cash equivalents	0			0
Trading securities	0			0
Debt Securities, Held-to-maturity, gross	124,020			138,515
Investment securities, Allowance for Credit Loss	0			0
Investment Securities, Amortized Cost, After Allowance for Credit Loss	124,020			138,515
Available for sale securities	473			473
Residential mortgage loans held for sale	7,248			7,218
Loans	22,846,124			21,891,223
Allowance for loan losses	0			0
Loans, net of allowance	22,846,124			21,891,223
Mortgage servicing rights	304,722			277,608
Derviative contracts, net of cash collateral, Assets, Fair value	0			0
Deposits with no stated maturity	30,588,466			33,018,863
Time deposits	2,672,789			1,431,245
Other borrowed funds	9,221,872			7,005,305
Subordinated debentures	0			0
Derivative contracts, net of cash collateral, Liabilities, Fair Value	0			0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	14,428,246			13,905,765
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,839,799			4,454,048
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Loans to individuals [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,578,079			3,531,410
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0			0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0			0
Debt Securities, Held-to-maturity, gross	0			0
Available for sale securities	0			0
Fair value option securities	0			0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0			0
Debt Securities, Held-to-maturity, gross	124,020			138,515
Available for sale securities	0			0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0			0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0			0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0			0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	0			0
Available for sale securities	0			0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Securities, Held-to-maturity, gross	0			0
Available for sale securities	$ 473			$ 473

[1] Carrying value includes $193 million of net unrealized loss which remains in Accumulated other comprehensive income ("AOCI") in the Consolidated Balance Sheets related to certain securities transferred during the second quarter of 2022 from the Available for Sale securities portfolio to the Investment securities portfolio.

[2] Carrying value includes $225 million of net unrealized loss which remains in Accumulated other comprehensive income ("AOCI") in the Consolidated Balance Sheets related to certain securities transferred during the second quarter of 2022 from the Available for Sale securities portfolio to the Investment securities portfolio.