EMPLOYEE BENEFIT PLANS (Schedule of Plan's Asset Allocations) (Details) (Pension Plans [Member])	Dec. 31, 2012	Dec. 31, 2011
PLAN ASSETS:
Asset allocations	100.00%	100.00%
Domestic Equities [Member]
PLAN ASSETS:
Asset allocations	22.00%	19.00%
Mutual Funds/ETFs [Member]
PLAN ASSETS:
Asset allocations	63.00%	71.00%
International Equity Securities [Member]
PLAN ASSETS:
Asset allocations	2.00%
Corporate Bonds [Member]
PLAN ASSETS:
Asset allocations	13.00%	10.00%
Ameriserv Financial, Inc. Common Stock [Member]
PLAN ASSETS:
Asset allocations	2.90%

Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e2446-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph d(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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