Fair Value of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 25, 2011	Dec. 26, 2010	Dec. 27, 2009
Fair Value of Financial Instruments [Abstract]
Fair value of available for sale investments, fair value option	$ 19,657	$ 21,767
Gain on available for sale investments, fair value option	61	1,218	1,019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, assets	19,669	21,791
Derivatives, assets	29,500	38,092
Total assets	49,169	59,883
Derivatives, liabilities	1,908
Reconciliation of fair value measurements of the Company's warrants [Roll Forward]
Balance at beginning of year	9,155	6,808
Gain (loss) from change in fair value	(5,431)	2,347
Balance at end of year	3,724	9,155	6,808
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, assets	12	24
Derivatives, assets	0	0
Total assets	12	24
Derivatives, liabilities	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, assets	19,657	21,767
Derivatives, assets	25,776	28,937
Total assets	45,433	50,704
Derivatives, liabilities	1,908
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, assets	0	0
Derivatives, assets	3,724	9,155
Total assets	3,724	9,155
Derivatives, liabilities	$ 0