Benefit Plans - Pension Assets by Fair Value Level (Details) - USD ($) $ in Thousands	Dec. 25, 2021	Dec. 26, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	$ 79,478	$ 78,480
Approximate percentage of mutual funds actively managed	78.00%	76.00%
Approximate percentage of mutual funds indexed funds	22.00%	24.00%
Percentage of mutual funds' assets invested in U.S equities	27.00%	27.00%
Percent of mutual funds assets invested in non US equities	73.00%	73.00%
Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	$ 292	$ 492
Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	71,465	71,084
Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	7,721	6,904
Cash and money market funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	292	492
Cash and money market funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	292	492
Cash and money market funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Cash and money market funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Mutual Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	71,465	71,084
Mutual Funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Mutual Funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	71,465	71,084
Mutual Funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Limited partnerships
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	7,721	6,904
Limited partnerships | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Limited partnerships | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	0	0
Limited partnerships | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Long-term asset	$ 7,721	$ 6,904