v2.4.0.6
Marketable Securities (Available for Sale Securities Measured at Estimated Fair Value on Recurring Basis) (Details) (USD $)
In Thousands, unless otherwise specified
Sep. 28, 2013
Dec. 29, 2012
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total $ 1,728,397 $ 1,641,395
Fair Value, Measurements, Recurring [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 1,728,397 1,641,395
Fair Value, Measurements, Recurring [Member] | Mortgage-Backed Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 518,840 650,895
Fair Value, Measurements, Recurring [Member] | Obligations of States and Political Subdivisions [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 690,615 499,857
Fair Value, Measurements, Recurring [Member] | Corporate Bond Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 420,345 399,941
Fair Value, Measurements, Recurring [Member] | Common Stock [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 27,435 22,982
Fair Value, Measurements, Recurring [Member] | Other securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 71,162 67,720
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 27,435 22,982
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Mortgage-Backed Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 0 0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Obligations of States and Political Subdivisions [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 0 0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Corporate Bond Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 0 0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Common Stock [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 27,435 22,982
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Other securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 0 0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 1,700,962 1,618,413
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Mortgage-Backed Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 518,840 650,895
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Obligations of States and Political Subdivisions [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 690,615 499,857
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate Bond Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 420,345 399,941
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Common Stock [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total 0 0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Total $ 71,162 $ 67,720