v2.4.0.8
Schedule of Fixed Income Securities in Unrealized Loss Positions (Detail) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2013
Schedule of Available-for-sale Securities [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value $ 695,161
Unrealized Losses Less Than 12 Months - Unrealized (3,721)
Unrealized Losses 12 Months or Greater - Fair Value 5,053
Unrealized Losses 12 Months or Greater - Unrealized (120)
Total - Fair Value 700,214
Total - Unrealized (3,841)
Municipal Notes And Bonds
  
Schedule of Available-for-sale Securities [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 65,792
Unrealized Losses Less Than 12 Months - Unrealized (449)
Total - Fair Value 65,792
Total - Unrealized (449)
US Treasury and Agencies
  
Schedule of Available-for-sale Securities [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 116,312
Unrealized Losses Less Than 12 Months - Unrealized (373)
Total - Fair Value 116,312
Total - Unrealized (373)
Government-Sponsored Enterprises
  
Schedule of Available-for-sale Securities [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 14,929
Unrealized Losses Less Than 12 Months - Unrealized (95)
Total - Fair Value 14,929
Total - Unrealized (95)
Foreign Government Bonds
  
Schedule of Available-for-sale Securities [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 13,700
Unrealized Losses Less Than 12 Months - Unrealized (25)
Total - Fair Value 13,700
Total - Unrealized (25)
Corporate Notes And Bonds
  
Schedule of Available-for-sale Securities [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 390,119
Unrealized Losses Less Than 12 Months - Unrealized (1,918)
Unrealized Losses 12 Months or Greater - Fair Value 895
Unrealized Losses 12 Months or Greater - Unrealized (27)
Total - Fair Value 391,014
Total - Unrealized (1,945)
Mortgage Backed Securities - Residential
  
Schedule of Available-for-sale Securities [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 24,952
Unrealized Losses Less Than 12 Months - Unrealized (282)
Total - Fair Value 24,952
Total - Unrealized (282)
Mortgage Backed Securities - Commercial
  
Schedule of Available-for-sale Securities [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 69,357
Unrealized Losses Less Than 12 Months - Unrealized (579)
Unrealized Losses 12 Months or Greater - Fair Value 4,158
Unrealized Losses 12 Months or Greater - Unrealized (93)
Total - Fair Value 73,515
Total - Unrealized $ (672)