XML 75 R63.htm IDEA: XBRL DOCUMENT v3.7.0.1
Junior Subordinated Debentures - Schedule of Junior Subordinated Debentures (Detail) - USD ($)
$ in Millions
6 Months Ended 12 Months Ended
Jun. 30, 2017
Dec. 31, 2016
Debt Instrument [Line Items]    
Junior subordinated debentures, Amount $ 256.4 $ 172.7 [1]
Trust Preferred Debentures [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Amount $ 172.7 $ 172.7
Trust Preferred Debentures [Member] | PXRE Capital Statutory Trust II [Member] | Argo Group [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date May 15, 2003 May 15, 2003
Junior subordinated debentures, Maturity date May 15, 2033 May 15, 2033
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 5.28% 5.00%
Junior subordinated debentures, Amount $ 18.1 $ 18.1
Trust Preferred Debentures [Member] | PXRE Capital Trust VI [Member] | Argo Group [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date Nov. 06, 2003 Nov. 06, 2003
Junior subordinated debentures, Maturity date Sep. 30, 2033 Sep. 30, 2033
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 5.20% 4.90%
Junior subordinated debentures, Amount $ 10.3 $ 10.3
Trust Preferred Debentures [Member] | Argonaut Group Statutory Trust I [Member] | Argo Group US [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date May 15, 2003 May 15, 2003
Junior subordinated debentures, Maturity date May 15, 2033 May 15, 2033
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 5.28% 5.00%
Junior subordinated debentures, Amount $ 15.5 $ 15.5
Trust Preferred Debentures [Member] | Argonaut Group Statutory Trust III [Member] | Argo Group US [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date Dec. 16, 2003 Dec. 16, 2003
Junior subordinated debentures, Maturity date Jan. 08, 2034 Jan. 08, 2034
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 5.26% 4.98%
Junior subordinated debentures, Amount $ 12.3 $ 12.3
Trust Preferred Debentures [Member] | Argonaut Group Statutory Trust IV [Member] | Argo Group US [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date Apr. 29, 2004 Apr. 29, 2004
Junior subordinated debentures, Maturity date Apr. 29, 2034 Apr. 29, 2034
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 5.03% 4.76%
Junior subordinated debentures, Amount $ 13.4 $ 13.4
Trust Preferred Debentures [Member] | Argonaut Group Statutory Trust V [Member] | Argo Group US [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date May 26, 2004 May 26, 2004
Junior subordinated debentures, Maturity date May 24, 2034 May 24, 2034
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 5.04% 4.77%
Junior subordinated debentures, Amount $ 12.3 $ 12.3
Trust Preferred Debentures [Member] | Argonaut Group Statutory Trust VI [Member] | Argo Group US [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date May 12, 2004 May 12, 2004
Junior subordinated debentures, Maturity date May 12, 2034 May 12, 2034
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 5.07% 4.79%
Junior subordinated debentures, Amount $ 13.4 $ 13.4
Trust Preferred Debentures [Member] | Argonaut Group Statutory Trust VII [Member] | Argo Group US [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date Sep. 17, 2004 Sep. 17, 2004
Junior subordinated debentures, Maturity date Dec. 15, 2034 Dec. 15, 2031
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 4.85% 4.56%
Junior subordinated debentures, Amount $ 15.5 $ 15.5
Trust Preferred Debentures [Member] | Argonaut Group Statutory Trust VIII [Member] | Argo Group US [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date Sep. 22, 2004 Sep. 22, 2004
Junior subordinated debentures, Maturity date Sep. 22, 2034 Sep. 22, 2034
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 4.84% 4.55%
Junior subordinated debentures, Amount $ 15.5 $ 15.5
Trust Preferred Debentures [Member] | Argonaut Group Statutory Trust IX [Member] | Argo Group US [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date Oct. 22, 2004 Oct. 22, 2004
Junior subordinated debentures, Maturity date Dec. 15, 2034 Dec. 15, 2034
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 4.85% 4.56%
Junior subordinated debentures, Amount $ 15.5 $ 15.5
Trust Preferred Debentures [Member] | Argonaut Group Statutory Trust X [Member] | Argo Group US [Member]    
Debt Instrument [Line Items]    
Junior subordinated debentures, Issue date Sep. 15, 2005 Sep. 15, 2005
Junior subordinated debentures, Maturity date Sep. 15, 2035 Sep. 15, 2035
Junior subordinated debentures, Rate Structure 2016 and 2015: 3M LIBOR + 4.10%  
Junior subordinated debentures, interest rate stated percentage 4.65% 4.36%
Junior subordinated debentures, Amount $ 30.9 $ 30.9
[1] Derived from audited consolidated financial statements.