Pension Benefits - Fair Value of Plan Assets (Details) - Pension Plan - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 26, 2021	Dec. 27, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	$ 1,145,933	$ 1,550,078	$ 1,585,221
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	1,145,933
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	205,306	312,854
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	617,944	837,485
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	322,683	399,739
U.S. Equities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	10,548	12,739
U.S. Equities | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	10,548	12,739
U.S. Equities | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
U.S. Equities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
U.S. Equities | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
International Equities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	23,448	29,453
International Equities | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	23,448	29,453
International Equities | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
International Equities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
International Equities | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Registered Investment Companies | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	171,310	270,662
Registered Investment Companies | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	171,310	270,662
Registered Investment Companies | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Registered Investment Companies | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Registered Investment Companies | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Common Collective Funds | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	288,489	370,042
Common Collective Funds | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Common Collective Funds | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Common Collective Funds | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Common Collective Funds | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	288,489	370,042
Corporate debt securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	531,033	710,413
Corporate debt securities | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Corporate debt securities | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	531,033	710,413
Corporate debt securities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Corporate debt securities | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
U.S. Treasury and Other Government Securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	46,279	52,520
U.S. Treasury and Other Government Securities | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
U.S. Treasury and Other Government Securities | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	46,279	52,520
U.S. Treasury and Other Government Securities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
U.S. Treasury and Other Government Securities | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Municipal securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	27,851	37,922
Municipal securities | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Municipal securities | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	27,851	37,922
Municipal securities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Municipal securities | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Other | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	12,781	36,630
Other | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Other | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	12,781	36,630
Other | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Other | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Cash and Cash Equivalents | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	15,064	7,229
Cash and Cash Equivalents | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Cash and Cash Equivalents | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Cash and Cash Equivalents | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Cash and Cash Equivalents | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	15,064	7,229
Private Equity | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	4,766	7,014
Private Equity | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Private Equity | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Private Equity | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Private Equity | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	4,766	7,014
Hedge Fund | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	14,364	15,454
Hedge Fund | Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Hedge Fund | Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Hedge Fund | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	0	0
Hedge Fund | Recurring | Investment Measured at Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined benefits plan, plan assets	$ 14,364	$ 15,454