Schedule of Debt (Parenthetical) (Detail)	12 Months Ended
Dec. 25, 2021	Dec. 26, 2020
Third Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Long term debt, due date	2025	2025
Revenue bonds, due in varying amounts periodically through 2029
Debt Instrument [Line Items]
Long term debt, due date	2029	2029
American & Foreign Power Company, Inc. 5% debentures, due 2030
Debt Instrument [Line Items]
Long term debt, due date	2030	2030
Long term debt, interest rate	5.00%	5.00%

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant