v3.25.2
Cover Page - shares
6 Months Ended
Jun. 30, 2025
Jul. 31, 2025
Cover [Abstract]    
Entity Address, Address Line One 23 Broad Street,  
Entity Address, City or Town Westerly,  
Entity Address, State or Province RI  
Entity Incorporation, State or Country Code RI  
Document Transition Report false  
Document Quarterly Report true  
Entity Registrant Name Washington Trust Bancorp Inc  
Entity Central Index Key 0000737468  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Document Type 10-Q  
Entity File Number 001-32991  
City Area Code 401  
Local Phone Number 348-1200  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Shell Company false  
Document Period End Date Jun. 30, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Entity Emerging Growth Company false  
Entity Small Business false  
Title of 12(g) Security COMMON STOCK, $.0625 PAR VALUE PER SHARE  
Trading Symbol WASH  
Security Exchange Name NASDAQ  
Entity Common Stock, Shares Outstanding   19,155,214
Entity Tax Identification Number 05-0404671  
Entity Address, Postal Zip Code 02891