v2.4.0.6
Schedule of Fixed Income Securities in Unrealized Loss Positions (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 23, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value $ 326,324
Unrealized Losses Less Than 12 Months - Unrealized (765)
Unrealized Losses 12 Months or Greater - Fair Value 2,351
Unrealized Losses 12 Months or Greater - Unrealized (38)
Total - Fair Value 328,675
Total - Unrealized (803)
Municipal Notes And Bonds
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 39,212
Unrealized Losses Less Than 12 Months - Unrealized (46)
Total - Fair Value 39,212
Total - Unrealized (46)
US Treasury and Agencies
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 33,860
Unrealized Losses Less Than 12 Months - Unrealized (28)
Total - Fair Value 33,860
Total - Unrealized (28)
Government-Sponsored Enterprises
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 3,513
Unrealized Losses Less Than 12 Months - Unrealized (2)
Total - Fair Value 3,513
Total - Unrealized (2)
Foreign Governments Bonds
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 7,601
Unrealized Losses Less Than 12 Months - Unrealized (5)
Total - Fair Value 7,601
Total - Unrealized (5)
Corporate Notes And Bonds
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 184,816
Unrealized Losses Less Than 12 Months - Unrealized (279)
Unrealized Losses 12 Months or Greater - Fair Value 295
Total - Fair Value 185,111
Total - Unrealized (279)
Mortgage Backed Securities- Residential
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 3,746
Unrealized Losses Less Than 12 Months - Unrealized (57)
Total - Fair Value 3,746
Total - Unrealized (57)
Mortgage Backed Securities - Commercial
  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Unrealized Losses Less Than 12 Months - Fair Value 53,576
Unrealized Losses Less Than 12 Months - Unrealized (348)
Unrealized Losses 12 Months or Greater - Fair Value 2,056
Unrealized Losses 12 Months or Greater - Unrealized (38)
Total - Fair Value 55,632
Total - Unrealized $ (386)