Loans and Allowance for Credit Losses, Loans by Portfolio Type (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	$ 6,410,911	$ 6,603,265
Loans, variable rate of interest	14,139,272	13,468,356
Loans, non-accrual	124,246	134,059
Total	20,674,429	20,205,680
Credit Commitments [Abstract]
Outstanding commitments to extend credit	12,500,000
Outstanding standby letters of credit	654,000
Commercial [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	3,343,185	3,360,117
Loans, variable rate of interest	9,479,667	9,072,244
Loans, non-accrual	60,337	74,104
Total	12,883,189	12,506,465
Commercial real estate [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	924,332	929,015
Loans, variable rate of interest	3,160,635	2,888,048
Loans, non-accrual	15,989	14,262
Total	4,100,956	3,831,325
Paycheck Protection Program [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	137,365	276,341
Loans, variable rate of interest	0	0
Loans, non-accrual	0	0
Total	137,365	276,341
Loans to individuals [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	2,006,029	2,037,792
Loans, variable rate of interest	1,498,970	1,508,064
Loans, non-accrual	47,920	45,693
Total	$ 3,552,919	$ 3,591,549

-- None. No documentation exists for this element. --

No definition available.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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- References

No definition available.

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- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522

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- Definition

Reflects the carrying amount of loans deemed to be questionable as to collection on which no interest is continuing to be recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5111-111524

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- Definition

Amount of loan with fixed rate of interest.

+ References

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- Definition

Amount of loan with variable or adjustable rate of interest.

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- Definition

Unused amount of commitments to extend credit to customers.

+ References

No definition available.

+ Details

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