v2.4.0.6
Summary of Gross Unrealized Losses of Fixed-maturities and Equity Securities (Detail) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2012
Contract
Investments, Unrealized Loss Position [Line Items]  
Fair Market Value $ 414,839
Unrealized Losses (12,625)
No. of Positions Held 130
Fair Market Value 95,305
Unrealized Losses (11,211)
No. of Positions Held 20
Total Fair Market Value 510,144
Total Unrealized Losses (23,836)
Common and preferred stock
  
Investments, Unrealized Loss Position [Line Items]  
Fair Market Value 10,377
Unrealized Losses (2,428)
No. of Positions Held 26
Fair Market Value 306
Unrealized Losses (32)
No. of Positions Held 1
Total Fair Market Value 10,683
Total Unrealized Losses (2,460)
U.S. treasury securities
  
Investments, Unrealized Loss Position [Line Items]  
Fair Market Value 3,160
Unrealized Losses (5)
No. of Positions Held 5
Total Fair Market Value 3,160
Total Unrealized Losses (5)
Municipal bonds
  
Investments, Unrealized Loss Position [Line Items]  
Fair Market Value 56,538
Unrealized Losses (87)
No. of Positions Held 14
Total Fair Market Value 56,538
Total Unrealized Losses (87)
Agency, residential mortgage backed securities
  
Investments, Unrealized Loss Position [Line Items]  
Fair Market Value 17,571
Unrealized Losses (320)
No. of Positions Held 1
Total Fair Market Value 17,571
Total Unrealized Losses (320)
Non-agency, residential mortgage backed securities
  
Investments, Unrealized Loss Position [Line Items]  
Fair Market Value 7,138
Unrealized Losses (728)
No. of Positions Held 2
Total Fair Market Value 7,138
Total Unrealized Losses (728)
Corporate Bonds | Finance
  
Investments, Unrealized Loss Position [Line Items]  
Fair Market Value 201,962
Unrealized Losses (6,063)
No. of Positions Held 48
Fair Market Value 86,509
Unrealized Losses (10,139)
No. of Positions Held 16
Total Fair Market Value 288,471
Total Unrealized Losses (16,202)
Corporate Bonds | Industrial
  
Investments, Unrealized Loss Position [Line Items]  
Fair Market Value 112,721
Unrealized Losses (2,551)
No. of Positions Held 32
Fair Market Value 2,813
Unrealized Losses (554)
No. of Positions Held 2
Total Fair Market Value 115,534
Total Unrealized Losses (3,105)
Corporate Bonds | Utilities
  
Investments, Unrealized Loss Position [Line Items]  
Fair Market Value 5,372
Unrealized Losses (443)
No. of Positions Held 2
Fair Market Value 5,677
Unrealized Losses (486)
No. of Positions Held 1
Total Fair Market Value 11,049
Total Unrealized Losses $ (929)