Disclosures about Fair Value of Assets and Liabilities - Quantitative Information about Unobservable Inputs (Details) $ in Thousands	Sep. 30, 2019 USD ($) item	Dec. 31, 2018 USD ($) item
Quantitative information about unobservable inputs
Mortgage servicing rights \| $	$ 71,989	$ 77,844
Mortgage servicing rights \| Level 3
Quantitative information about unobservable inputs
Mortgage servicing rights \| $	71,989	77,844
Collateral-dependent impaired loans \| Level 3
Quantitative information about unobservable inputs
Collateral-dependent impaired loans \| $	$ 1,600	$ 2,639
Marketability discount (as a percent)	0.37
Collateral-dependent impaired loans \| Level 3 \| Minimum
Quantitative information about unobservable inputs
Marketability discount (as a percent)		0.17
Collateral-dependent impaired loans \| Level 3 \| Maximum
Quantitative information about unobservable inputs
Marketability discount (as a percent)		0.59
Discount Rate \| Mortgage servicing rights \| Level 3 \| Minimum
Quantitative information about unobservable inputs
Servicing asset, measurement input	0.08	0.08
Discount Rate \| Mortgage servicing rights \| Level 3 \| Maximum
Quantitative information about unobservable inputs
Servicing asset, measurement input	0.13	0.13
Constant Prepayment Rate \| Mortgage servicing rights \| Level 3 \| Minimum
Quantitative information about unobservable inputs
Servicing asset, measurement input	0.01	0.01
Constant Prepayment Rate \| Mortgage servicing rights \| Level 3 \| Maximum
Quantitative information about unobservable inputs
Servicing asset, measurement input	0.39	0.30
Interest Rate Lock Commitments \| Level 3
Quantitative information about unobservable inputs
Derivative assets \| $	$ 296	$ 70
Derivative liabilities \| $	$ 8
Interest Rate Lock Commitments \| Measurement Input, Maturity \| Level 3 \| Minimum
Quantitative information about unobservable inputs
Loan closing rates (as a percent)	0.73	0.95
Loan closing rates (as a percent)	0.73
Interest Rate Lock Commitments \| Measurement Input, Maturity \| Level 3 \| Maximum
Quantitative information about unobservable inputs
Loan closing rates (as a percent)	0.99	1.00
Loan closing rates (as a percent)	0.99

The fair value amount of impaired loans.

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- Definition

Value of input used to measure collateral-dependent impaired loans.

+ References

No definition available.

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- Definition

Value of input used to measure derivative asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

+ Details

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- Definition

Value of input used to measure derivative liability.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

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-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746

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- Definition

Value of input used to measure servicing asset.

+ References

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