Fair Value of Assets and Liabilities - Assets Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 29, 2018	Dec. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in equity securities	$ 10,312	$ 10,993
Mutual funds	9,112	7,962
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in equity securities	10,312	10,993
Mutual funds	9,112	7,962
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in equity securities	0	0
Mutual funds	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in equity securities	0	0
Mutual funds	$ 0	$ 0