Fair Value Measurements, Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020		Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	$ 2,245,480			$ 1,623,921
Investment Securities, Gross Amortized Cost	256,740			293,418
Investment securities, Allowance for Credit Loss	739	[1]		0
Investment securities, net of allowance	256,001			293,418
Available for sale securities	12,817,269			11,269,643
Fair value option securities	134,756			1,098,577
Residential mortgage loans held for sale	295,290			182,271
Loans	23,803,300			21,750,987
Allowance for loan losses	(419,777)			(210,759)	$ (204,432)	$ (202,534)	$ (207,457)
Loans, net of allowance	23,383,523			21,540,228
Mortgage servicing rights	97,644		$ 97,971	201,886	193,661	208,308	259,254
Derviative contracts, net of cash collateral, Assets, Fair value	593,568			323,375
Time deposits	2,007,973			2,217,849
Subordinated debentures	275,986			275,923
Derivative contracts, net of cash collateral, Liabilities, Fair Value	446,328			251,128
Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,565,706			14,031,650
Allowance for loan losses	(290,277)			(118,187)	(106,643)	(106,397)	(102,226)
Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,693,700			4,433,783
Allowance for loan losses	(71,575)			(51,805)	$ (54,350)	$ (54,188)	$ (60,026)
Loans to individuals [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	3,446,569			2,084,172
Allowance for loan losses	(57,925)
Paycheck Protection Program
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,097,325
Allowance for loan losses	0
U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	5,181			44,264
Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	2,150,759			1,504,651
Investment Securities, Gross Amortized Cost	9,317			10,676
Available for sale securities	9,384,998			8,046,096
Fair value option securities	134,756			1,088,660
Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	30,533			26,196
Investment Securities, Gross Amortized Cost	76,109			93,653
Available for sale securities	51,601			1,861
U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	509			1,600
Fair value option securities	0			9,917
Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	34,873			41,609
Commercial agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	3,334,409			3,178,005
Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	59,007			34,726
Investment Securities, Gross Amortized Cost	171,314			189,089
Available for sale securities	10,879			472
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	658,612			735,836
Interest-bearing cash and cash equivalents	347,759			522,985
Trading securities	2,245,480			1,623,921
Investment Securities, Gross Amortized Cost	256,740
Investment securities, Allowance for Credit Loss	(739)
Investment securities, net of allowance	256,001			293,418
Available for sale securities	12,817,269			11,269,643
Fair value option securities				1,098,577
Residential mortgage loans held for sale	295,290			182,271
Loans	23,803,300			21,750,987
Allowance for loan losses	(419,777)			(210,759)
Loans, net of allowance	23,383,523			21,540,228
Mortgage servicing rights	97,644			201,886
Derviative contracts, net of cash collateral, Assets, Fair value	593,568			323,375
Deposits with no stated maturity	32,965,027			25,403,319
Time deposits	2,007,973			2,217,849
Other borrowed funds	3,745,081			8,345,405
Subordinated debentures	275,986			275,923
Derivative contracts, net of cash collateral, Liabilities, Fair Value	446,328			251,128
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,565,706			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	4,693,700			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	3,446,569
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	2,097,325
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	5,181			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	2,150,759			1,504,651
Investment Securities, Gross Amortized Cost	9,317
Investment securities, net of allowance				10,676
Available for sale securities	9,384,998			8,046,096
Fair value option securities	134,756			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	30,533			26,196
Investment Securities, Gross Amortized Cost	76,109
Investment securities, net of allowance				93,653
Available for sale securities	51,601			1,861
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities				14,084
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	59,007			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	509			1,600
Fair value option securities				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	34,873			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	3,334,409			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	171,314
Investment securities, net of allowance				189,089
Available for sale securities	10,879			472
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	658,612			735,836
Interest-bearing cash and cash equivalents	347,759			522,985
Trading securities	2,245,480			1,623,921
Investment Securities, Gross Amortized Cost	284,929
Investment securities, Allowance for Credit Loss	0
Investment securities, net of allowance	284,929			314,402
Available for sale securities	12,817,269			11,269,643
Fair value option securities				1,098,577
Residential mortgage loans held for sale	295,290			182,271
Loans	23,697,211			21,689,329
Allowance for loan losses	0			0
Loans, net of allowance	23,697,211			21,689,329
Mortgage servicing rights	97,644			201,886
Derviative contracts, net of cash collateral, Assets, Fair value	593,568			323,375
Deposits with no stated maturity	32,965,027			25,403,319
Time deposits	2,019,474			2,212,467
Other borrowed funds	3,741,686			8,315,860
Subordinated debentures	269,083			284,627
Derivative contracts, net of cash collateral, Liabilities, Fair Value	446,328			251,128
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,500,846			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	4,673,857			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	3,452,042
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	2,070,466
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	5,181			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	2,150,759			1,504,651
Investment Securities, Gross Amortized Cost	10,219
Investment securities, net of allowance				11,164
Available for sale securities	9,384,998			8,046,096
Fair value option securities	134,756			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	30,533			26,196
Investment Securities, Gross Amortized Cost	80,368
Investment securities, net of allowance				96,897
Available for sale securities	51,601			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				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	59,007			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	509			1,600
Fair value option securities				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	34,873			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	3,334,409			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	194,342
Investment securities, net of allowance				206,341
Available for sale securities	10,879			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	658,612			735,836
Interest-bearing cash and cash equivalents	347,759			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	509			1,600
Fair value option securities				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	11,713			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
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	509			1,600
Fair value option securities				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	2,245,480			1,623,921
Investment Securities, Gross Amortized Cost	97,963
Investment securities, Allowance for Credit Loss	0
Investment securities, net of allowance	97,963			116,267
Available for sale securities	12,816,288			11,267,571
Fair value option securities				1,088,660
Residential mortgage loans held for sale	286,785			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	581,855			314,431
Deposits with no stated maturity	0			0
Time deposits	0			0
Other borrowed funds	0			0
Subordinated debentures	269,083			284,627
Derivative contracts, net of cash collateral, Liabilities, Fair Value	446,328			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	5,181			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	2,150,759			1,504,651
Investment Securities, Gross Amortized Cost	10,219
Investment securities, net of allowance				11,164
Available for sale securities	9,384,998			8,046,096
Fair value option securities	134,756			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	30,533			26,196
Investment Securities, Gross Amortized Cost	80,368
Investment securities, net of allowance				96,897
Available for sale securities	51,601			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				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	59,007			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
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	34,873			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	3,334,409			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	7,376
Investment securities, net of allowance				8,206
Available for sale securities	10,407			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	186,966
Investment securities, Allowance for Credit Loss	0
Investment securities, net of allowance	186,966			198,135
Available for sale securities	472			472
Fair value option securities				0
Residential mortgage loans held for sale	8,505			8,313
Loans	23,697,211			21,689,329
Allowance for loan losses	0			0
Loans, net of allowance	23,697,211			21,689,329
Mortgage servicing rights	97,644			201,886
Derviative contracts, net of cash collateral, Assets, Fair value	0			0
Deposits with no stated maturity	32,965,027			25,403,319
Time deposits	2,019,474			2,212,467
Other borrowed funds	3,741,686			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	13,500,846			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	4,673,857			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	3,452,042
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	2,070,466
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
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
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	186,966
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.