LONG-TERM DEBT (Details) - USD ($)	12 Months Ended
	Dec. 30, 2017	Oct. 18, 2017	Oct. 17, 2017	Dec. 31, 2016
Long-term debt:
Aggregate principal amount	$ 250,200,000			$ 250,200,000
Debt issuance costs	(6,112,000)			(6,646,000)
Total long-term debt	754,854,000			755,646,000
Less current installments of long-term debt	966,000			851,000
Long-term debt, excluding current installments	$ 753,888,000			$ 754,795,000
Effective interest rate (as a percent)	2.00%			1.00%
Minimum aggregate maturities of long-term debt
2016	$ 966,000
2017	765,000
2018	250,969,000
2019	773,000
2020	582,000
5.00% senior unsecured notes due 2044
Long-term debt:
Aggregate principal amount	250,000,000			$ 250,000,000
Unamortized premium on senior unsecured notes	$ 1,102,000
Redemption price of notes, stated as a percentage of principal amount (as a percent)	100.00%
Interest rate on notes (as a percent)	5.00%
5.25% senior unsecured notes due 2054
Long-term debt:
Aggregate principal amount	$ 250,000,000			250,000,000
Unamortized premium on senior unsecured notes	$ 3,210,000
Redemption price of notes, stated as a percentage of principal amount (as a percent)	100.00%
Interest rate on notes (as a percent)	5.30%
Unamortized discount on 5.00% and 5.25% senior unsecured notes
Long-term debt:
Unamortized premium on senior unsecured notes	$ (4,312,000)			(4,360,000)
6.625% senior unsecured notes due in April 2020
Long-term debt:
Aggregate principal amount	250,200,000
Unamortized premium on senior unsecured notes	$ 2,545,000			3,557,000
Redemption price of notes, stated as a percentage of principal amount (as a percent)	100.00%
Interest rate on notes (as a percent)	6.60%
Revolving credit agreement
Long-term debt:
Total long-term debt	$ 0			0
Maximum borrowing capacity		$ 600,000,000
Increase in borrowing capacity, maximum	200,000,000
Additional borrowing capacity	585,200,000
Standby letters of credit outstanding	$ 14,800,000
Revolving credit agreement | Minimum
Long-term debt:
Basis points added to variable rate (as a percent)	0.00%
Revolving credit agreement | Maximum
Long-term debt:
Basis points added to variable rate (as a percent)	6250.00%
Revolving credit agreement | LIBOR
Long-term debt:
Variable interest rate basis	LIBOR (based on a 1, 2, 3 or 6 month interest period, as selected by the Company)
Basis points added to variable rate (as a percent)	10000.00%
Variable interest rate, base period	1 month
Revolving credit agreement | LIBOR | Minimum
Long-term debt:
Basis points added to variable rate (as a percent)	10000.00%
Revolving credit agreement | LIBOR | Maximum
Long-term debt:
Basis points added to variable rate (as a percent)	16250.00%
Revolving credit agreement | Prime lending rate
Long-term debt:
Variable interest rate basis	prime lending rate
Revolving credit agreement | Federal Funds rate
Long-term debt:
Variable interest rate basis	Federal Funds rate
Basis points added to variable rate (as a percent)	5000.00%
Revolving credit agreement, foreign currency
Long-term debt:
Maximum borrowing capacity		$ 400,000,000	$ 200,000,000
IDR Bonds
Long-term debt:
Total long-term debt	$ 8,500,000			8,500,000
Other notes
Long-term debt:
Total long-term debt	4,033,000			$ 4,395,000
Short Term Bank Lines Of Credit
Long-term debt:
Additional borrowing capacity	113,300,000
Balance	$ 113,400,000