The accretable amount of acquired receivables from a business combination.

No definition available.

Name:	sybt_BusinessCombinationAcquiredReceivablesAccretableAmount
Namespace Prefix:	sybt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of acquired receivable from business combination, excluding certain loans and debt securities acquired in transfer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=116869197&loc=d3e4845-128472

+ Details

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

- Definition

For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the gross contractual amounts receivable, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=116869197&loc=d3e4845-128472

+ Details

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

- Definition

The amount of the loan's contractually required payments receivable in excess of the amount of its cash flows expected to be collected. This relates to loans with deteriorating of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

No definition available.

+ Details

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

- Definition

Amount of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118938799&loc=d3e13503-111538

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=118939070&loc=d3e15032-111544

+ Details

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

- Definition

Amount of reclassification (to) from nonaccretable difference (from) to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=118939070&loc=d3e15032-111544

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118938799&loc=d3e13503-111538

+ Details

Name:	us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsToFromNonaccretableDifference
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair value at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118938799&loc=d3e13503-111538

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=118939070&loc=d3e15032-111544

+ Details

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

- Definition

Amount of contractually required payments receivable at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=118939070&loc=d3e15032-111544

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118938799&loc=d3e13503-111538

+ Details

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

- Details

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

- Details

Name:	us-gaap_CreditLossStatusAxis=us-gaap_FinancialAssetAcquiredAndNoCreditDeteriorationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditLossStatusAxis=us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=sybt_CommercialAndIndustrialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=sybt_ConstructionAndDevelopmentExcludingUndevelopedLandPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=sybt_UndevelopmentLandPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=sybt_RealEstateMortgagePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=sybt_OneToFourFamilyResidentialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=sybt_HomeEquityFirstLienMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=sybt_HomeEquityJuniorLienMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 4 - Loans and Leases - Loans Acquired in King Acquisition (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	May 01, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Loans		$ 0	$ 0	$ 0	$ 0
Loans		1,575		1,575			$ 432
Loans		(1,575)		(1,575)			0
Loans		$ (0)	$ 85	$ (0)	$ 85	$ 62	$ 68	$ 95	$ 106
King Bancorp Inc. [Member]
Loans	$ 165,744
Loans	(136)
Loans	164,029
Loans	(1,579)
King Bancorp Inc. [Member] \| Financial Asset Acquired and No Credit Deterioration [Member]
Loans	164,165
Loans	0
Loans	(136)
Loans	164,029
King Bancorp Inc. [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Loans	1,579
Loans	(1,579)
Loans	0
Loans	0
Commercial and Industrial Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired and No Credit Deterioration [Member]
Loans	8,249
Loans	0
Loans	(23)
Loans	8,226
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired and No Credit Deterioration [Member]
Loans	10,764
Loans	0
Loans	43
Loans	10,807
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Loans	0
Loans	0
Loans	0
Loans	0
Undevelopment Land Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired and No Credit Deterioration [Member]
Loans	7,974
Loans	0
Loans	43
Loans	8,017
Undevelopment Land Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Loans	0
Loans	0
Loans	0
Loans	0
Real Estate Mortgage Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired and No Credit Deterioration [Member]
Loans	135,650
Loans	0
Loans	(126)
Loans	135,524
Real Estate Mortgage Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired and No Credit Deterioration [Member] \| Commercial Real Estate [Member]
Loans	84,219
Loans	0
Loans	(456)
Loans	83,763
Real Estate Mortgage Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired and No Credit Deterioration [Member] \| One to Four Family Residential [Member]
Loans	50,556
Loans	0
Loans	322
Loans	50,878
Real Estate Mortgage Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired and No Credit Deterioration [Member] \| Home Equity First Lien [Member]
Loans	196
Loans	0
Loans	3
Loans	199
Real Estate Mortgage Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired and No Credit Deterioration [Member] \| Home Equity Junior Lien [Member]
Loans	679
Loans	0
Loans	5
Loans	684
Real Estate Mortgage Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Loans	1,579
Loans	(1,579)
Loans	0
Loans	0
Real Estate Mortgage Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired with Credit Deterioration [Member] \| Commercial Real Estate [Member]
Loans	1,351
Loans	(1,351)
Loans	0
Loans	0
Real Estate Mortgage Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired with Credit Deterioration [Member] \| One to Four Family Residential [Member]
Loans	228
Loans	(228)
Loans	0
Loans	0
Real Estate Mortgage Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired with Credit Deterioration [Member] \| Home Equity First Lien [Member]
Loans	0
Loans	0
Loans	0
Loans	0
Real Estate Mortgage Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired with Credit Deterioration [Member] \| Home Equity Junior Lien [Member]
Loans	0
Loans	0
Loans	0
Loans	0
Consumer Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired and No Credit Deterioration [Member]
Loans	1,528
Loans	0
Loans	(73)
Loans	1,455
Consumer Portfolio Segment [Member] \| King Bancorp Inc. [Member] \| Financial Asset Acquired with Credit Deterioration [Member]
Loans	0
Loans	0
Loans	0
Loans	$ 0