v3.25.2
Document and Entity Information
Aug. 18, 2025
Entity Listings [Line Items]  
Document Type 8-K
Amendment Flag false
Document Period End Date Aug. 18, 2025
Entity File Number 001-15259
Entity Registrant Name Argo Group International Holdings, Inc.
Entity Central Index Key 0001091748
Entity Incorporation, State or Country Code DE
Entity Tax Identification Number 98-0214719
Entity Address, Address Line One 501 7th Avenue
Entity Address, Address Line Two 7th Floor
Entity Address, City or Town New York
Entity Address, State or Province NY
Entity Address, Postal Zip Code 10018
City Area Code 210
Local Phone Number 321-8400
Entity Emerging Growth Company false
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
6.500% Senior Notes due 2042 issued by Argo Group US, Inc. and The Guarantee With Respects Thereto [Member]  
Entity Listings [Line Items]  
Title of 12(b) Security 6.500% Senior Notes due 2042 issued by Argo Group US, Inc. and The Guarantee With Respects Thereto
Trading Symbol ARGD
Security Exchange Name NYSE
Depositary Shares, Each Representing a 1/1000th Interest in 7.00% Resettable Fixed Rate Preferred Stock, Series A, Par Value $1.00 Per Share [Member]  
Entity Listings [Line Items]  
Title of 12(b) Security Depositary Shares, Each Representing a 1/1000th Interest in 7.00% Resettable Fixed Rate Preferred Stock, Series A, Par Value $1.00 Per Share
Trading Symbol ARGO/PA
Security Exchange Name NYSE