Goodwill and Other Intangible Assets, Mortgage Servicing Rights Roll-Forward (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Mortgage servicing rights
Mortgage servicing rights at beginning of period		$ 67,607	$ 68,433
Additions from acquisition		1,357	0
Additions		11,495	11,606
Amortization		(16,416)	(12,432)
Mortgage servicing rights at end of period	$ 64,043	64,043	67,607
Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward]
Valuation allowance at beginning of period		(302)	(239)
(Additions) recoveries, net	(18,000)	(18,481)	(63)
Valuation allowance at end of period	(18,782)	(18,782)	(302)
Mortgage servicing rights, net	45,261	45,261	67,306
Fair value of mortgage servicing rights	45,303	45,303	72,532
Portfolio of residential mortgage loans serviced for others (“servicing portfolio”)	$ 8,218,839	$ 8,218,839	$ 8,488,969
Mortgage servicing rights, net to servicing portfolio	0.55%	0.55%	0.79%
Mortgage servicing rights expense(a)	$ 34,897	$ 34,897	$ 12,494

MSR Addition from Business Combination

No definition available.

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- Definition

Includes the amortization of mortgage servicing rights and additions/recoveries to the valuation allowance of mortgage servicing rights, and is a component of mortgage banking, net in the consolidated statements of income.

+ References

No definition available.

+ Details

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- Definition

Mortgage servicing rights, net to servicing portfolio.

+ References

No definition available.

+ Details

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- Definition

Portfolio of residential mortgage loans serviced for others ("servicing portfolio").

+ References

No definition available.

+ Details

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- Definition

Net amortized carrying amount (balance) as of the balance sheet date of an asset representing net future revenues from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs and allowances related to servicing arrangements.

+ References

No definition available.

+ Details

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- Definition

Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122492-111745

Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

+ Details

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- Definition

Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

+ Details

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- Definition

Amount of amortization of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

+ Details

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- Definition

Fair value of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

+ Details

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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- Definition

Reflects the estimated amount of impairment as of the balance sheet date of recognized servicing assets that are being amortized in proportion to and over the period of estimated net servicing income or loss.

+ References

+ Details

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- Definition

Amount of increase (decrease) in the valuation allowance for impairment of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer from expenses (recoveries) recognized.

+ References

+ Details

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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