Fixed interest rate of advances made and reported by Federal Home Loan Bank (FHLBank).

No definition available.

Name:	by_FederalHomeLoanBankAdvancesFixedInterestRate
Namespace Prefix:	by_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Federal home loan bank advances maximum borrowing capacity as percentage of total assets.

+ References

No definition available.

+ Details

Name:	by_FederalHomeLoanBankAdvancesMaximumBorrowingCapacityAsPercentageOfAssets
Namespace Prefix:	by_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Federal home loan bank fixed rate advances.

+ References

No definition available.

+ Details

Name:	by_FederalHomeLoanBankFixedRateAdvances
Namespace Prefix:	by_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Federal Reserve Bank discount window borrowing.

+ References

No definition available.

+ Details

Name:	by_FederalReserveBankDiscountWindowBorrowing
Namespace Prefix:	by_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of credit facility extended maturity date.

+ References

No definition available.

+ Details

Name:	by_LineOfCreditFacilityExtendedMaturityDate
Namespace Prefix:	by_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Ratio applied to the conversion of required investment in Federal Home Loan Bank (FHL Bank) $1 for every $ 20.

+ References

No definition available.

+ Details

Name:	by_RequiredInvestmentInFederalHomeLoanBankConversionRatio
Namespace Prefix:	by_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of the sum of the obligations to contract holders to provide to them an agreed upon rate of return pursuant to the terms of the underlying contract. These contracts represent lending by the contract holders to the entity in return for a guaranteed (primarily fixed) interest rate until maturity, unless called earlier if the contracts provide that option to the contract holders (usually institutions). There is little or no insurance risk for the entity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

Name:	us-gaap_BorrowingsUnderGuaranteedInvestmentAgreements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of Federal Home Loan Bank (FHLBank) advances to member financial institutions.

+ References

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvances
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Interest rate of advances made and reported by Federal Home Loan Bank (FHLBank).

+ References

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Description of interest rate for borrowing under credit facility. Includes, but is not limited to, terms and method for determining interest rate.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The effective interest rate during the reporting period.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

+ Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481372/852-10-55-10

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

Name:	us-gaap_ShortTermBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The portion of the carrying amount of short-term borrowings outstanding as of the balance sheet date, which accrues interest at a rate subject to change from time to time.

+ References

No definition available.

+ Details

Name:	us-gaap_ShortTermDebtPercentageBearingVariableInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=us-gaap_FederalReserveBankAdvancesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=by_CorrespondentBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=by_RidgestoneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=by_CreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=by_AmendedCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=by_FourthAmendmentRevolvingCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Other Borrowings - Additional Information (Details) - USD ($)			12 Months Ended
	May 25, 2025	Oct. 10, 2019	Dec. 31, 2024	Dec. 31, 2023	May 24, 2024	Jan. 22, 2024	Oct. 13, 2016
Line Of Credit Facility [Line Items]
Federal Reserve Bank discount window borrowing			$ 0	$ 0
Federal Home Loan Bank Variable Rate Advances			250,000,000
Federal Home Loan Bank fixed rate advances			$ 325,000,000
Federal home loan bank advances, Fixed interest rate			4.46%
Federal Home Loan Bank, Advances, Interest Rate			4.51%
Federal home loan bank, required investment conversion ratio			4.5
Federal home loan bank advances maximum borrowing capacity as percentage of total assets			35.00%
Line of credit facility, amount			$ 0	11,250,000
Term Loan			$ 11,667,000	$ 18,333,000
Variable term loan, Interest rate			6.83%	7.64%
Line of Credit Facility, Interest Rate				7.39%
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity					$ 15,000,000
Forecast
Line Of Credit Facility [Line Items]
Line of credit facility, extended maturity date	May 25, 2025
Federal Reserve Bank Advances
Line Of Credit Facility [Line Items]
Debt instrument, interest rate						4.91%
Bank Term Funding Program						$ 200,000,000
Correspondent Bank \| Ridgestone
Line Of Credit Facility [Line Items]
Line of credit facility, interest rate terms			The amended revolving line of credit bears interest at either SOFR plus 205 basis points or Prime Rate minus 75 basis points, not to be less than 2.00%, based on the Company’s election, which is required to be communicated at least three business days prior to the commencement of an interest period. If the Company fails to provide timely notification, the interest rate will be Prime Rate minus 75 basis points.
Correspondent Bank \| Credit agreement \| Ridgestone
Line Of Credit Facility [Line Items]
Line of credit facility, amount							$ 30,000,000
Correspondent Bank \| Amended Credit Agreement \| Ridgestone \| SOFR
Line Of Credit Facility [Line Items]
Interest rate spread		205.00%
Correspondent Bank \| Amended Credit Agreement \| Ridgestone \| Prime Rate
Line Of Credit Facility [Line Items]
Interest rate spread		75.00%
Correspondent Bank \| Fourth Amendment Revolving Credit Agreement \| Ridgestone
Line Of Credit Facility [Line Items]
Line of credit facility, amount			$ 0				$ 15,000,000
Line of credit facility, interest rate terms			At December 31, 2024 the line of credit had no outstanding balance. At December 31, 2023, the line of credit had a $11.3 million outstanding balance and an interest rate of 7.39%.