FAIR VALUE MEASUREMENT (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 30, 2012		Dec. 25, 2011
Commodity derivative assets	$ 1,821		$ 2,870
Commodity derivative liabilities	(1,530)		(2,723)
Short-Term Investments [Member]
Investments in available- for-sale securities, Fair value	0		157
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member]
Investments in available- for-sale securities, Fair value	0		0
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member]
Investments in available- for-sale securities, Fair value	0		157
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member]
Investments in available- for-sale securities, Fair value			0
Long Term Investments [Member]
Investments in available- for-sale securities, Fair value	0		497
Long Term Investments [Member] | Fair Value, Inputs, Level 1 [Member]
Investments in available- for-sale securities, Fair value	0		0
Long Term Investments [Member] | Fair Value, Inputs, Level 2 [Member]
Investments in available- for-sale securities, Fair value			438
Long Term Investments [Member] | Fair Value, Inputs, Level 3 [Member]
Investments in available- for-sale securities, Fair value			59
Options Held [Member]
Commodity derivative liabilities	0	[1]	(603)	[1]
Options Held [Member] | Fair Value, Inputs, Level 1 [Member]
Commodity derivative liabilities	0		0
Options Held [Member] | Fair Value, Inputs, Level 2 [Member]
Commodity derivative liabilities	0		(603)
Options Held [Member] | Fair Value, Inputs, Level 3 [Member]
Commodity derivative liabilities	0		0
Future [Member]
Commodity derivative assets	1,821	[2]	2,870	[2]
Commodity derivative liabilities	(1,530)	[1]	(2,120)	[1]
Future [Member] | Fair Value, Inputs, Level 1 [Member]
Commodity derivative assets	1,821		2,870
Commodity derivative liabilities	(1,530)		(2,120)
Future [Member] | Fair Value, Inputs, Level 2 [Member]
Commodity derivative assets	0		0
Commodity derivative liabilities	0		0
Future [Member] | Fair Value, Inputs, Level 3 [Member]
Commodity derivative assets	0		0
Commodity derivative liabilities	$ 0		$ 0

[1] Commodity derivative liabilities are included in Accrued expenses and other current liabilities on the Consolidated Balance Sheet.

[2] Commodity derivative assets are included in Prepaid expenses and other current assets on the Consolidated Balance Sheet.