Fair Value Measurements, Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2020		Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	$ 1,196,105			$ 1,623,921
Investment Securities, Gross Amortized Cost	269,616			293,418
Investment securities, Allowance for Credit Loss	1,628	[1]		0
Investment securities, net of allowance	267,988			293,418
Available for sale securities	12,475,919			11,269,643
Fair value option securities	722,657			1,098,577
Residential mortgage loans held for sale	319,357			182,271
Loans	24,155,890			21,750,987
Allowance for loan losses	(435,597)			(210,759)	$ (202,534)	$ (205,340)	$ (207,457)
Loans, net of allowance	23,720,293			21,540,228
Mortgage servicing rights	97,971		$ 110,828	201,886	208,308	238,193	259,254
Derviative contracts, net of cash collateral, Assets, Fair value	651,553			323,375
Time deposits	2,352,760			2,217,849
Subordinated debentures	275,973			275,923
Derivative contracts, net of cash collateral, Liabilities, Fair Value	610,020			251,128
Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	14,158,510			14,031,650
Allowance for loan losses	(310,422)			(118,187)	(106,397)	(103,577)	(102,226)
Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,554,144			4,433,783
Allowance for loan losses	(68,756)			(51,805)	$ (54,188)	$ (58,134)	$ (60,026)
Loans to individuals [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,361,808			2,084,172
Allowance for loan losses	(56,419)
Paycheck Protection Program
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,081,428
Allowance for loan losses	0
U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	4,237			44,264
Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,146,454			1,504,651
Investment Securities, Gross Amortized Cost	9,812			10,676
Available for sale securities	9,147,238			8,046,096
Fair value option securities	629,915			1,088,660
Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	22,710			26,196
Investment Securities, Gross Amortized Cost	84,239			93,653
Available for sale securities	31,240			1,861
U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	912			1,600
Fair value option securities	92,742			9,917
Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	35,250			41,609
Commercial agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	3,260,807			3,178,005
Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	22,699			34,726
Investment Securities, Gross Amortized Cost	175,565			189,089
Available for sale securities	472			472
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	762,453			735,836
Interest-bearing cash and cash equivalents	485,319			522,985
Trading securities	1,196,105			1,623,921
Investment Securities, Gross Amortized Cost	269,616
Investment securities, Allowance for Credit Loss	(1,628)
Investment securities, net of allowance	267,988			293,418
Available for sale securities	12,475,919			11,269,643
Fair value option securities	722,657			1,098,577
Residential mortgage loans held for sale	319,357			182,271
Loans	24,155,890			21,750,987
Allowance for loan losses	(435,597)			(210,759)
Loans, net of allowance	23,720,293			21,540,228
Mortgage servicing rights	97,971			201,886
Derviative contracts, net of cash collateral, Assets, Fair value	651,553			323,375
Deposits with no stated maturity	31,539,554			25,403,319
Time deposits	2,352,760			2,217,849
Other borrowed funds	4,531,165			8,345,405
Subordinated debentures	275,973			275,923
Derivative contracts, net of cash collateral, Liabilities, Fair Value	610,020			251,128
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	14,158,510			14,031,650
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,554,144			4,433,783
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans				2,084,172
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Loans to individuals [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,361,808
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans				1,201,382
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Paycheck Protection Program
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,081,428
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	4,237			44,264
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	1,146,454			1,504,651
Investment Securities, Gross Amortized Cost	9,812
Investment securities, net of allowance				10,676
Available for sale securities	9,147,238			8,046,096
Fair value option securities	629,915			1,088,660
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	22,710			26,196
Investment Securities, Gross Amortized Cost	84,239
Investment securities, net of allowance				93,653
Available for sale securities	31,240			1,861
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	5			14,084
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	22,699			34,726
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	912			1,600
Fair value option securities	92,742			9,917
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	35,250			41,609
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	3,260,807			3,178,005
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment Securities, Gross Amortized Cost	175,565
Investment securities, net of allowance				189,089
Available for sale securities	472			472
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	762,453			735,836
Interest-bearing cash and cash equivalents	485,319			522,985
Trading securities	1,196,105			1,623,921
Investment Securities, Gross Amortized Cost	299,126
Investment securities, Allowance for Credit Loss	0
Investment securities, net of allowance	299,126			314,402
Available for sale securities	12,475,919			11,269,643
Fair value option securities	722,657			1,098,577
Residential mortgage loans held for sale	319,357			182,271
Loans	24,052,102			21,689,329
Allowance for loan losses	0			0
Loans, net of allowance	24,052,102			21,689,329
Mortgage servicing rights	97,971			201,886
Derviative contracts, net of cash collateral, Assets, Fair value	651,553			323,375
Deposits with no stated maturity	31,539,554			25,403,319
Time deposits	2,367,446			2,212,467
Other borrowed funds	4,527,814			8,315,860
Subordinated debentures	273,293			284,627
Derivative contracts, net of cash collateral, Liabilities, Fair Value	610,020			251,128
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	14,038,257			13,966,221
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,558,274			4,422,717
Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans				2,098,093
Estimate of Fair Value, Fair Value Disclosure [Member] | Loans to individuals [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,393,293
Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans				1,202,298
Estimate of Fair Value, Fair Value Disclosure [Member] | Paycheck Protection Program
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,062,278
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	4,237			44,264
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	1,146,454			1,504,651
Investment Securities, Gross Amortized Cost	10,734
Investment securities, net of allowance				11,164
Available for sale securities	9,147,238			8,046,096
Fair value option securities	629,915			1,088,660
Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	22,710			26,196
Investment Securities, Gross Amortized Cost	88,623
Investment securities, net of allowance				96,897
Available for sale securities	31,240			1,861
Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	5			14,084
Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	22,699			34,726
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	912			1,600
Fair value option securities	92,742			9,917
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	35,250			41,609
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	3,260,807			3,178,005
Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment Securities, Gross Amortized Cost	199,769
Investment securities, net of allowance				206,341
Available for sale securities	472			472
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	762,453			735,836
Interest-bearing cash and cash equivalents	485,319			522,985
Trading securities	0			0
Investment Securities, Gross Amortized Cost	0
Investment securities, Allowance for Credit Loss	0
Investment securities, net of allowance	0			0
Available for sale securities	912			1,600
Fair value option securities	92,742			9,917
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	66,207			8,944
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	0			0
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] | Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans				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
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans				0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Paycheck Protection Program
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
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] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0			0
Investment Securities, Gross Amortized Cost	0
Investment securities, net of allowance				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 and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0			0
Investment Securities, Gross Amortized Cost	0
Investment securities, net of allowance				0
Available for sale securities	0			0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed 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] | 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	912			1,600
Fair value option securities	92,742			9,917
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]
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]
Investment Securities, Gross Amortized Cost	0
Investment securities, net of allowance				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	1,196,105			1,623,921
Investment Securities, Gross Amortized Cost	107,405
Investment securities, Allowance for Credit Loss	0
Investment securities, net of allowance	107,405			116,267
Available for sale securities	12,474,535			11,267,571
Fair value option securities	629,915			1,088,660
Residential mortgage loans held for sale	309,672			173,958
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	585,346			314,431
Deposits with no stated maturity	0			0
Time deposits	0			0
Other borrowed funds	0			0
Subordinated debentures	273,293			284,627
Derivative contracts, net of cash collateral, Liabilities, Fair Value	610,020			251,128
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] | Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans				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
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans				0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Paycheck Protection Program
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	4,237			44,264
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	1,146,454			1,504,651
Investment Securities, Gross Amortized Cost	10,734
Investment securities, net of allowance				11,164
Available for sale securities	9,147,238			8,046,096
Fair value option securities	629,915			1,088,660
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	22,710			26,196
Investment Securities, Gross Amortized Cost	88,623
Investment securities, net of allowance				96,897
Available for sale securities	31,240			1,861
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	5			14,084
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	22,699			34,726
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 option 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	35,250			41,609
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]
Available for sale securities	3,260,807			3,178,005
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]
Investment Securities, Gross Amortized Cost	8,048
Investment securities, net of allowance				8,206
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
Investment Securities, Gross Amortized Cost	191,721
Investment securities, Allowance for Credit Loss	0
Investment securities, net of allowance	191,721			198,135
Available for sale securities	472			472
Fair value option securities	0			0
Residential mortgage loans held for sale	9,685			8,313
Loans	24,052,102			21,689,329
Allowance for loan losses	0			0
Loans, net of allowance	24,052,102			21,689,329
Mortgage servicing rights	97,971			201,886
Derviative contracts, net of cash collateral, Assets, Fair value	0			0
Deposits with no stated maturity	31,539,554			25,403,319
Time deposits	2,367,446			2,212,467
Other borrowed funds	4,527,814			8,315,860
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	14,038,257			13,966,221
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	4,558,274			4,422,717
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans				2,098,093
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	3,393,293
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans				1,202,298
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Paycheck Protection Program
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,062,278
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [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
Investment Securities, Gross Amortized Cost	0
Investment securities, net of allowance				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 and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0			0
Investment Securities, Gross Amortized Cost	0
Investment securities, net of allowance				0
Available for sale securities	0			0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed 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] | 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 option 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]
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]
Investment Securities, Gross Amortized Cost	191,721
Investment securities, net of allowance				198,135
Available for sale securities	$ 472			$ 472

[1] Effective with the adoption of FASB ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) on January 1, 2020.