XML 127 R111.htm IDEA: XBRL DOCUMENT v3.8.0.1

Other Borrowings - Summary of Short-term Credit Lines Available for Use (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Federal Reserve Bank of Chicago Discount Window Line
Debt Instrument [Line Items]
Short-term credit lines available for use	$ 144,248	$ 110,600
Available Federal Funds Line
Debt Instrument [Line Items]
Short-term credit lines available for use	$ 55,000	$ 20,000

X

- Definition

Short-term line of credit available for use.

+ References

No definition available.

+ Details

Name:	by_ShortTermLinesOfCreditAvailableForUse
Namespace Prefix:	by_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

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

X

- Details

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