Derivative Hedging Instruments (Details) - USD ($)	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Derivative, Notional Amount	$ 0	$ 0
Derivative Instruments, increase (decrease) in interest expense	$ 0	$ 0
Derivative Instruments Weighted Average Interest Rate Received Paid	0.00%	0.00%
Derivative Financial Instruments, Liabilities [Member] \| Swap [Member]
Derivative, Swap Type	FAIR VALUE	FAIR VALUE
Derivative Liability, Notional Amount	$ (19,983,363)	$ (17,057,388)
Derivative Instruments, Repricing Frequency	MONTHLY	MONTHLY
Derivative Instruments, increase (decrease) in interest expense	$ 41,743	$ 72,920
Derivative Instruments Weighted Average Interest Rate Received Paid	(4.20%)	(3.42%)
Derivative Financial Instruments, Assets [Member] \| Swap [Member]
Derivative, Swap Type	FAIR VALUE	FAIR VALUE
Derivative Asset, Notional Amount	$ 19,983,363	$ 17,057,388
Derivative Instruments, Repricing Frequency	MONTHLY	MONTHLY
Derivative Instruments, increase (decrease) in interest expense	$ (41,743)	$ (72,920)
Derivative Instruments Weighted Average Interest Rate Received Paid	4.20%	3.42%

Description for repricing frequency of derivative instruments.

No definition available.

Name:	asrv_DerivativeInstrumentsRepricingFrequency
Namespace Prefix:	asrv_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of interest received(Paid) during the period under Interest Rate swap transaction.

+ References

No definition available.

+ Details

Name:	asrv_DerivativeInstrumentsWeightedAverageInterestRateReceivedPaid
Namespace Prefix:	asrv_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This amount represents the increase (decrease) in interest expense (not fair value) of interest rate swaps.

+ References

No definition available.

+ Details

Name:	asrv_IncreaseDecreaseInInterestExpense
Namespace Prefix:	asrv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Nominal or face amount used to calculate payments on the derivative asset.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeAssetNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Nominal or face amount used to calculate payments on the derivative liability.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeLiabilityNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Indicates whether the entity pays a variable or fixed price on a price risk swap.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_SwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_DerivativeFinancialInstrumentsAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: