EMPLOYEE BENEFIT PLANS - Additional information (Details)	12 Months Ended
	Dec. 31, 2025 USD ($) Y	Dec. 31, 2024 USD ($)	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Minimum number of annual hours	1,000
Maximum percent of plan assets comprised of AmeriServ Financial, Inc. common stock	4.00%
Percentage gain combined from other sources	0.99%
Defined contribution plan, employer matching contribution, percent of match	2.00%			6.00%
Defined contribution plan maximum annual contribution per union employee percent	4.00%
Non-elective contribution by employer for non union employees				4.00%
Non-elective contribution by employer for union employees			4.00%
Defined contribution plan, cost	$ 1,000,000	$ 982,000
Defined Contribution Plan assets in common stocks	$ 534,000	390,000
Period of investment performance	20 years
Other expense
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation plan expense	$ 9,000	19,000
Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match			4.00%
Employer matching	1.00%			3.00%
Other liabilities
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation liability	$ 183,000	350,000
Equity securities | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	60.00%
Equity securities | Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Plan assets of the company's common stock	$ 2,400,000	1,800,000
Cash and cash equivalents | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	100.00%
Cash and cash equivalents | Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%
Debt securities | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	100.00%
Debt securities | Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.00%
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Requisite service period	5 years
Number of consecutive calendar years | Y	5
Period of employment	10 years
Maximum percent of plan assets comprised of AmeriServ Financial, Inc. common stock	4.00%
Settlement charge	$ 0	$ 471,000
Defined benefit plan percent of assets comprised of entity common stock	3.60%	2.80%
Defined benefit plan, expected future employer contributions, next fiscal year	$ 0
Pension Plan | Other assets
Defined Benefit Plan Disclosure [Line Items]
Assets for pension benefits	$ 36,100,000	$ 31,400,000