Schedule of Debt (Parenthetical) (Detail)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014
Recourse Debt | 7.35% debentures, due 2016
Debt Instrument [Line Items]
Long term debt, due date	2016
Long term debt, interest rate	7.35%
Recourse Debt | 7.35% debentures, due 2016 | Current Liability
Debt Instrument [Line Items]
Long term debt, due date	2016	2016
Long term debt, interest rate	7.35%	7.35%
Recourse Debt | 7.35% debentures, due 2016 | Noncurrent Liability
Debt Instrument [Line Items]
Long term debt, due date	2016	2016
Long term debt, interest rate	7.35%	7.35%
Recourse Debt | Senior Secured Notes, due 2019
Debt Instrument [Line Items]
Long term debt, due date	2019	2019
Recourse Debt | Revenue bonds, due in varying amounts periodically through 2029
Debt Instrument [Line Items]
Long term debt, due date	2029	2029
Recourse Debt | 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%
Non-Recourse Debt
Debt Instrument [Line Items]
Long term debt, due date	2019	2019
Long term debt, interest rate	5.42%	5.42%