XML 14 R1.htm IDEA: XBRL DOCUMENT v3.21.1
Document And Entity Information - shares
 3 Months Ended
Mar. 31, 2021
May 01, 2021
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2021  
Document Fiscal Year Focus 2021  
Document Fiscal Period Focus Q1  
Entity Registrant Name AMERISERV FINANCIAL INC /PA/  
Entity Central Index Key 0000707605  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Entity Current Reporting Status Yes  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Interactive Data Current Yes  
Entity Common Stock, Shares Outstanding   17,069,000
COMMON STOCK    
Document Information [Line Items]    
Trading Symbol ASRV  
Title of 12(b) Security Common Stock  
Security Exchange Name NASDAQ  
Beneficial Unsecured Securities    
Document Information [Line Items]    
Trading Symbol ASRVP  
Title of 12(b) Security Beneficial Unsecured Securities  
Security Exchange Name NASDAQ