XML 68 R131.htm IDEA: XBRL DOCUMENT
v3.20.1

Fair Value Measurement - Summary of Unobservable Inputs Used in Fair Value Measurements on Recurring Basis Categorized Within Level 3 of Fair Value Hierarchy (Details) - Fair Value, Measurements, Recurring - Level 3 | 12 Months Ended
--- | ---
Dec. 31, 2019
Single Issuer Trust Preferred |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Impact to Valuation from an Increased or Higher Input Value | Decrease
Debt Instrument, Valuation Technique [Extensible List] | us-gaap:ValuationTechniqueDiscountedCashFlowMember
Debt Instrument, Measurement Input [Extensible List] | us-gaap:MeasurementInputDiscountRateMember
Single Issuer Trust Preferred | Minimum |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Unobservable Inputs | 0.051
Single Issuer Trust Preferred | Maximum |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Unobservable Inputs | 0.064
Single Issuer Trust Preferred | Weighted Average |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Unobservable Inputs | 0.056
Servicing Assets |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Servicing Asset, Valuation Technique [Extensible List] | us-gaap:ValuationTechniqueDiscountedCashFlowMember
Servicing Assets | Prepayment Speeds |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Impact to Valuation from an Increased or Higher Input Value | Decrease
Servicing Assets | Prepayment Speeds | Minimum |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Unobservable Inputs | 0.029
Servicing Assets | Prepayment Speeds | Maximum |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Unobservable Inputs | 0.249
Servicing Assets | Prepayment Speeds | Weighted Average |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Unobservable Inputs | 0.147
Servicing Assets | Discount Rate |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Impact to Valuation from an Increased or Higher Input Value | Decrease
Servicing Assets | Discount Rate | Minimum |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Unobservable Inputs | 0.056
Servicing Assets | Discount Rate | Maximum |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Unobservable Inputs | 0.321
Servicing Assets | Discount Rate | Weighted Average |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Unobservable Inputs | 0.125
Servicing Assets | Expected Weighted Average Loan life |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Impact to Valuation from an Increased or Higher Input Value | Increase
Servicing Assets | Expected Weighted Average Loan life | Minimum |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Expected weighted average loan life | 1 month 6 days
Servicing Assets | Expected Weighted Average Loan life | Maximum |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Expected weighted average loan life | 8 years 10 months 24 days
Servicing Assets | Expected Weighted Average Loan life | Weighted Average |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
Expected weighted average loan life | 4 years 3 months 18 days

X
- Definition Fair value input expected weighted average loan life weighted average range assumptions expected term. + References No definition available. + Details
Name: | by_FairValueInputExpectedWeightedAverageLoanLifeWeightedAverageRangeAssumptionsExpectedTerm
Namespace Prefix: | by_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value measurement change in valuation of input value description. + References No definition available. + Details
Name: | by_FairValueMeasurementChangeInValuationOfInputValueDescription
Namespace Prefix: | by_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of input used to measure debt instrument, including, but not limited to, convertible and non-convertible debt. + 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=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_DebtInstrumentMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Indicates measurement input for debt instrument, including, but not limited to, convertible and non-convertible debt. + 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)(1) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 31 -URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14210-108612 + Details
Name: | us-gaap_DebtInstrumentMeasurementInputExtensibleList
Namespace Prefix: | us-gaap_
Data Type: | srt-types:extensibleListItemType
Balance Type: | na
Period Type: | instant

X
- Definition Indicates valuation technique for measuring debt instrument, including, but not limited to, convertible and non-convertible debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 31 -URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14210-108612 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_DebtInstrumentValuationTechniqueExtensibleList
Namespace Prefix: | us-gaap_
Data Type: | srt-types:extensibleListItemType
Balance Type: | na
Period Type: | instant

X
- 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. + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of input used to measure servicing 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=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_ServicingAssetMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Indicates valuation technique for measuring servicing 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)(1) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_ServicingAssetValuationTechniqueExtensibleList
Namespace Prefix: | us-gaap_
Data Type: | srt-types:extensibleListItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=by_SingleIssuerTrustPreferredSecurityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=by_ServicingAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputPrepaymentRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputExpectedTermMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |