Fair Value Measurements (Details) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 30, 2018 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | $ 388,077 | $ 371,301 |
Long-term AFS securities | 185,083 | 213,558 |
Total long term debt | 248,000 | 247,000 |
Long-term debt, fair value | 259,000 | 260,000 |
Level 1 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Deferred compensation | 21,447 | 23,211 |
Level 2 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Deferred compensation | 0 | 0 |
Level 3 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Deferred compensation | 0 | 0 |
Fair Value | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Deferred compensation | 21,447 | 23,211 |
Debt Securities | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 388,077 | 371,301 |
Long-term AFS securities | 185,083 | 213,558 |
Debt Securities | Level 1 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Long-term AFS securities | 0 | 0 |
Debt Securities | Level 2 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 388,077 | 371,301 |
Long-term AFS securities | 185,083 | 213,558 |
Debt Securities | Level 3 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Long-term AFS securities | 0 | 0 |
Corporate debt securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 141,145 | 140,168 |
Long-term AFS securities | 107,292 | 129,624 |
Corporate debt securities | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 141,145 | 140,168 |
Long-term AFS securities | 107,292 | 129,624 |
Corporate debt securities | Level 1 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Long-term AFS securities | 0 | 0 |
Corporate debt securities | Level 2 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 141,145 | 140,168 |
Long-term AFS securities | 107,292 | 129,624 |
Corporate debt securities | Level 3 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Long-term AFS securities | 0 | 0 |
U.S. Treasury securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 121,067 | 107,485 |
Long-term AFS securities | 38,561 | 46,737 |
U.S. Treasury securities | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 121,067 | 107,485 |
Long-term AFS securities | 38,561 | 46,737 |
U.S. Treasury securities | Level 1 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Long-term AFS securities | 0 | 0 |
U.S. Treasury securities | Level 2 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 121,067 | 107,485 |
Long-term AFS securities | 38,561 | 46,737 |
U.S. Treasury securities | Level 3 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Long-term AFS securities | 0 | 0 |
U.S. governmental agency securities | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 87,819 | 91,974 |
Long-term AFS securities | 39,230 | 37,197 |
U.S. governmental agency securities | Level 1 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Long-term AFS securities | 0 | 0 |
U.S. governmental agency securities | Level 2 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 87,819 | 91,974 |
Long-term AFS securities | 39,230 | 37,197 |
U.S. governmental agency securities | Level 3 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Long-term AFS securities | 0 | 0 |
Certificates of deposit | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 21,688 | 23,497 |
Certificates of deposit | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 21,688 | 23,497 |
Certificates of deposit | Level 1 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Certificates of deposit | Level 2 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 21,688 | 23,497 |
Certificates of deposit | Level 3 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Commercial paper | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 16,358 | 8,177 |
Commercial paper | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 16,358 | 8,177 |
Commercial paper | Level 1 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Commercial paper | Level 2 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 16,358 | 8,177 |
Commercial paper | Level 3 | Recurring | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Short-term AFS securities | 0 | 0 |
Life Insurance Product Line [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Other Assets, Miscellaneous | $ 41,800 | $ 38,100 |