v3.26.3
Cover
Nov. 02, 2026
Jul. 29, 2026
Cover [Abstract]    
Document Type 8-K  
Document Period End Date Nov. 02, 2026  
Entity Registrant Name Waystar Holding Corp.  
Entity Incorporation, State or Country Code DE  
Entity File Number 001-42125  
Entity Tax Identification Number 84-2886542  
Entity Address, Address Line One 1550 Digital Drive  
Entity Address, Address Line Two #300  
Entity Address, City or Town Lehi  
Entity Address, State or Province UT  
Entity Address, Postal Zip Code 84043  
City Area Code 844  
Local Phone Number 492-9782  
Written Communications false  
Soliciting Material false  
Pre-commencement Tender Offer false  
Pre-commencement Issuer Tender Offer false  
Title of 12(b) Security   Common Stock, par value $0.01 per share
Trading Symbol   WAY
Security Exchange Name   NASDAQ
Entity Emerging Growth Company false  
Amendment Flag false  
Entity Central Index Key 0001990354  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q3