Update to Significant Accounting Policies - Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 30, 2018
Carrying Value
Measurement of financial assets and liabilities at fair value on a recurring basis
Cash surrender value of life insurance policies	$ 32,027	$ 27,751
Interest rate swap assets		4,905
Interest rate swap liabilities	6,184
Measured on Recurring Basis | Level 1
Measurement of financial assets and liabilities at fair value on a recurring basis
Cash surrender value of life insurance policies	32,027	27,751
Measured on Recurring Basis | Level 2
Measurement of financial assets and liabilities at fair value on a recurring basis
Interest rate swap assets		$ 4,905
Interest rate swap liabilities	$ 6,184