Note 15 - Mortgage Banking Activities - Mortgage Banking Income (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Net gain on sale of mortgage loans held for sale	$ 92	$ 1,196
Net change in fair value recognized on loans held for sale	(27)	0
Net change in fair value recognized on rate lock loan commitments	392	0
Net gain recognized	636	1,196
Loan servicing income	702	255
Amortization	(481)	(252)
Change in mortgage servicing rights valuation allowance	0	0
Net servicing income recognized	221	3
Other mortgage banking income	146	245
Total Mortgage banking income	1,003	1,444
Foreign Exchange Forward [Member]
Net change in fair value recognized on forward contracts	$ 179	$ 0

Net gain or loss on loans held-for-sale.

No definition available.

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Balance Type:	credit
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- Definition

Net gain or loss on rate lock loan commitments.

+ References

No definition available.

+ Details

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- Definition

The amount of gain (loss) on the sale of mortgage loans and fair value changes in loans and derivatives.

+ References

No definition available.

+ Details

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- Definition

The amount of loan servicing income.

+ References

No definition available.

+ Details

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Namespace Prefix:	sybt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of mortgage banking income (loss).

+ References

No definition available.

+ Details

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Namespace Prefix:	sybt_
Data Type:	xbrli:monetaryItemType
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- Definition

Amount of other mortgage banking income.

+ References

No definition available.

+ Details

Name:	sybt_MortgageBankingIncomeOther
Namespace Prefix:	sybt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of net servicing income (loss).

+ References

No definition available.

+ Details

Name:	sybt_NetServicingIncomeLoss
Namespace Prefix:	sybt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The periodic amortization (in proportion to and over the period of estimated net servicing income or loss) of capitalized servicing rights, which contractually entitle the servicer to receive fees and ancillary revenues for performing billing, collection, disbursement and recordkeeping services in connection with a mortgage portfolio. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (a)(4)
-URI https://asc.fasb.org/extlink&oid=128311188&loc=d3e122739-111746

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5618551-113959

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- Definition

The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans made to finance real estate acquisitions. This element refers to the gain (loss) and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=123605502&loc=d3e21310-158488

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 310
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
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-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=123605549&loc=d3e21493-158490

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Data Type:	xbrli:monetaryItemType
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- Definition

The adjustment to the carrying value of the rights retained or purchased to service mortgages. These adjustments are made when the estimate of the fair value is changed. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (a)(6)
-URI https://asc.fasb.org/extlink&oid=128311188&loc=d3e122739-111746

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Balance Type:	debit
Period Type:	duration

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