DISCLOSURES ABOUT FAIR VALUE MEASUREMENTS - Schedule of assets measured and recorded at fair value on a non-recurring basis (Details) $ in Thousands	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Disclosures about Fair Value Measurements and Financial Instruments
Individually evaluated loans with carrying value	$ 0	$ 1,600
Specific valuation allowance		3
Individually evaluated loans		$ 1,600
Other real estate owned and repossessed assets	15
Impaired loans
Disclosures about Fair Value Measurements and Financial Instruments
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Other real estate owned and repossessed assets
Disclosures about Fair Value Measurements and Financial Instruments
Other Real Estate Owned, Valuation Technique [Extensible Enumeration]		asrv:AppraisalOfCollateralMember
Other Real Estate Owned, Measurement Input [Extensible Enumeration]		us-gaap:MeasurementInputAppraisedValueMember, Measurement Input, Liquidation expenses [Member]
Fair Value Measurements, Nonrecurring Basis
Disclosures about Fair Value Measurements and Financial Instruments
Impaired loans		$ 1,583
Other real estate owned and repossessed assets	15	39
Fair Value Measurements, Nonrecurring Basis \| Level 1
Disclosures about Fair Value Measurements and Financial Instruments
Impaired loans		0
Other real estate owned and repossessed assets	0	0
Fair Value Measurements, Nonrecurring Basis \| Level 2
Disclosures about Fair Value Measurements and Financial Instruments
Impaired loans		0
Other real estate owned and repossessed assets	0	0
Fair Value Measurements, Nonrecurring Basis \| Level 3
Disclosures about Fair Value Measurements and Financial Instruments
Impaired loans		1,583
Other real estate owned and repossessed assets	15	39
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Impaired loans
Disclosures about Fair Value Measurements and Financial Instruments
Impaired loans		1,583
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Other real estate owned and repossessed assets
Disclosures about Fair Value Measurements and Financial Instruments
Impaired loans	$ 15	$ 39
Other real estate owned and repossessed assets, Measurement Input	0.63	0.52
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Other real estate owned and repossessed assets \| Measurement Input, Liquidation expenses [Member]
Disclosures about Fair Value Measurements and Financial Instruments
Other real estate owned and repossessed assets, Measurement Input	0.33
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Minimum \| Impaired loans
Disclosures about Fair Value Measurements and Financial Instruments
Loan, Measurement Input		0
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Minimum \| Other real estate owned and repossessed assets \| Measurement Input, Liquidation expenses [Member]
Disclosures about Fair Value Measurements and Financial Instruments
Other real estate owned and repossessed assets, Measurement Input		0.10
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Maximum \| Impaired loans
Disclosures about Fair Value Measurements and Financial Instruments
Loan, Measurement Input		1
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Maximum \| Other real estate owned and repossessed assets \| Measurement Input, Liquidation expenses [Member]
Disclosures about Fair Value Measurements and Financial Instruments
Other real estate owned and repossessed assets, Measurement Input		0.39
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Wgtd Ave \| Impaired loans
Disclosures about Fair Value Measurements and Financial Instruments
Loan, Measurement Input		0.002
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Wgtd Ave \| Other real estate owned and repossessed assets
Disclosures about Fair Value Measurements and Financial Instruments
Other real estate owned and repossessed assets, Measurement Input	0.63	0.52
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Wgtd Ave \| Other real estate owned and repossessed assets \| Measurement Input, Liquidation expenses [Member]
Disclosures about Fair Value Measurements and Financial Instruments
Other real estate owned and repossessed assets, Measurement Input		0.11
Fair Value Measurements, Nonrecurring Basis \| Level 3 \| Wgtd Ave \| Other real estate owned and repossessed assets \| Measurement Input, Liquidation expenses [Member]
Disclosures about Fair Value Measurements and Financial Instruments
Other real estate owned and repossessed assets, Measurement Input	0.33

Amount of individually evaluated loans for credit losses.

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Amount of individually evaluated loans related allowance.

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Amount of individually evaluated loans with carrying value.

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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.

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Value of input used to measure loan, held for sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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Indicates measurement input for loan held for sale.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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Indicates valuation technique for measuring loan held for sale.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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Carrying amount as of the balance sheet date of other real estate and foreclosed assets. Other real estate may include real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. Foreclosed assets include all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(4))
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Value of input used to measure real estate owned by financial institution by financial institution which is not directly related to its business.

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Indicates measurement input for real estate owned by financial institution which is not directly related to its business.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Fair value portion of receivables, including, but not limited to, trade account receivables, note receivables, and loan receivables.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-10

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