Benefit Plans - Pension Assets by Fair Value Level (Details) - USD ($) $ in Thousands	Dec. 29, 2018	Dec. 30, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	$ 164,603	$ 186,336
Approximate percentage of mutual funds actively managed	61.00%	66.00%
Approximate percentage of mutual funds indexed funds	39.00%	34.00%
Percentage of mutual funds' assets invested in U.S equities	5.00%	5.00%
Percent of mutual funds assets invested in non US equities	35.00%	41.00%
Percent of mutual funds assets invested in US fixed income securities	59.00%	52.00%
Percent of mutual funds assets invested in non US fixed income securities	1.00%	2.00%
Approximate percentage of common stock invested in major industry		91.00%
Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	$ 12,984	$ 24,889
Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	146,591	156,442
Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	5,028	5,005
Cash and Cash Equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	12,984	5,364
Cash and Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	12,984	5,364
Cash and Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Cash and Cash Equivalents [Member] | Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Defined Benefit Plan, Equity Securities, Common Stock [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		11,113
Defined Benefit Plan, Equity Securities, Common Stock [Member] | Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		11,113
Defined Benefit Plan, Equity Securities, Common Stock [Member] | Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		0
Defined Benefit Plan, Equity Securities, Common Stock [Member] | Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset		0
Mutual Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	146,591	164,854
Mutual Funds [Member] | Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	8,412
Mutual Funds [Member] | Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	146,591	156,442
Mutual Funds [Member] | Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Limited Partnerships [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	5,028	5,005
Limited Partnerships [Member] | Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Limited Partnerships [Member] | Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Limited Partnerships [Member] | Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	$ 5,028	$ 5,005