Employee Benefit Plans - Target Asset Allocation of Plan Assets (Details) - Pension benefits	Dec. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	100.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	15.00%
Equity Securities | Minimum
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	5.00%
Equity Securities | Maximum
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	20.00%
Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	85.00%
Debt Securities | Minimum
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	80.00%
Debt Securities | Maximum
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	95.00%