Regulatory Capital (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Summarized regulatory capital ratio of company
Tangible common equity ratio	7.64%us-gaap_TangibleCapitalToTangibleAssets
Consolidated [Member]
Summarized regulatory capital ratio of company
Total Capital (To RWA), Actual Amount	$ 131,581	$ 131,497
Total Capital (To RWA), Actual Ratio	14.68%	14.80%
Total Capital (To RWA), For Capital Adequacy Purposes Amount	71,688	71,066
Total Capital (To RWA), For Capital Adequacy Purposes Ratio	8.00%	8.00%
Total Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	89,609	88,833
Total Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00%	10.00%
Common Equity Tier 1 Capital (To RWA), Actual Amount	88,966
Common Equity Tier 1 Capital (To RWA), Actual Ratio	9.93%
Common Equity Tier 1 Capital (To RWA), For Capital Adequacy Purposes Amount	40,324
Common Equity Tier 1 Capital (To RWA), For Capital Adequacy Purposes Ratio	4.50%
Common Equity Tier 1 Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	58,246
Common Equity Tier 1 Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	6.50%
Tier 1 Capital (To RWA), Actual Amount	120,995	120,992
Tier 1 Capital (To RWA), Actual Ratio	13.50%	13.62%
Tier 1 Capital (To RWA), For Capital Adequacy Purposes Amount	53,766	35,533
Tier 1 Capital (To RWA), For Capital Adequacy Purposes Ratio	6.00%	4.00%
Tier 1 Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	71,688	53,300
Tier 1 Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	8.00%	6.00%
Tier 1 Capital (To Average Assets), Actual Amount	120,995	120,992
Tier 1 Capital (To Average Assets), Actual Ratio	11.24%	11.34%
Tier 1 Capital (To Average Assets), For Capital Adequacy Purposes Amount	43,072	42,662
Tier 1 Capital (To Average Assets), For Capital Adequacy Purposes Ratio	4.00%	4.00%
Tier 1 Capital (To Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	53,839	53,327
Tier 1 Capital (To Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	5.00%	5.00%
AmeriServ Financial Bank [Member]
Summarized regulatory capital ratio of company
Total Capital (To RWA), Actual Amount	105,692	106,084
Total Capital (To RWA), Actual Ratio	11.92%	12.07%
Total Capital (To RWA), For Capital Adequacy Purposes Amount	70,925	70,305
Total Capital (To RWA), For Capital Adequacy Purposes Ratio	8.00%	8.00%
Total Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	88,657	87,881
Total Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00%	10.00%
Common Equity Tier 1 Capital (To RWA), Actual Amount	95,106
Common Equity Tier 1 Capital (To RWA), Actual Ratio	10.73%
Common Equity Tier 1 Capital (To RWA), For Capital Adequacy Purposes Amount	39,896
Common Equity Tier 1 Capital (To RWA), For Capital Adequacy Purposes Ratio	4.50%
Common Equity Tier 1 Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	57,627
Common Equity Tier 1 Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	6.50%
Tier 1 Capital (To RWA), Actual Amount	95,106	95,579
Tier 1 Capital (To RWA), Actual Ratio	10.73%	10.88%
Tier 1 Capital (To RWA), For Capital Adequacy Purposes Amount	53,194	35,153
Tier 1 Capital (To RWA), For Capital Adequacy Purposes Ratio	6.00%	4.00%
Tier 1 Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	70,925	52,729
Tier 1 Capital (To RWA), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	8.00%	6.00%
Tier 1 Capital (To Average Assets), Actual Amount	95,106	95,579
Tier 1 Capital (To Average Assets), Actual Ratio	9.06%	9.19%
Tier 1 Capital (To Average Assets), For Capital Adequacy Purposes Amount	41,988	41,608
Tier 1 Capital (To Average Assets), For Capital Adequacy Purposes Ratio	4.00%	4.00%
Tier 1 Capital (To Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 52,485	$ 52,010
Tier 1 Capital (To Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	5.00%	5.00%

Common equity Tier 1 Risk Based Capital as defined in the regulations.

No definition available.

Name:	asrv_CommonEquityTierOneRiskBasedCapital
Namespace Prefix:	asrv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The minimum amount of common equity Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

No definition available.

+ Details

Name:	asrv_CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacy
Namespace Prefix:	asrv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The minimum common equity Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

No definition available.

+ Details

Name:	asrv_CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	asrv_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of common equity Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

+ References

No definition available.

+ Details

Name:	asrv_CommonEquityTierOneRiskBasedCapitalRequiredToBeWellCapitalized
Namespace Prefix:	asrv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The Common equity Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

+ References

No definition available.

+ Details

Name:	asrv_CommonEquityTierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	asrv_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Common equity Tier 1 capital divided by risk weighted assets as defined by regulations.

+ References

No definition available.

+ Details

Name:	asrv_CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets
Namespace Prefix:	asrv_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of total capital as defined in the regulations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6490092&loc=d3e47304-110998

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1H

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1H

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=6490092&loc=d3e47080-110998

+ Details

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

- Definition

The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

+ Details

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

- Definition

The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1H

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826

+ Details

Name:	us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

+ Details

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

- Definition

The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

+ Details

Name:	us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Total Capital divided by risk weighted assets as defined in the regulations.

+ References

+ Details

Name:	us-gaap_CapitalToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tangible Capital divided by Tangible assets as defined in the regulations.

+ References

+ Details

Name:	us-gaap_TangibleCapitalToTangibleAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

+ References

+ Details

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

- Details

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

- Definition

The minimum amount of Tier 1 Leverage Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

+ Details

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

- Definition

The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

+ References

+ Details

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

- Definition

The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier 1 Leverage Capital divided by average assets as defined in the regulations.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier 1 Risk Based Capital as defined in the regulations.

+ References

+ Details

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

- Definition

The minimum amount of Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

+ Details

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

- Definition

The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

+ References

+ Details

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

- Definition

The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier 1 capital divided by risk weighted assets as defined by regulations.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=asrv_AmeriservFinancialBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_ConsolidatedEntitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: