Fair Value of Financial Instruments, Significant Unobservable Inputs Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2016	Mar. 29, 2015	Dec. 27, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of year	$ (28,360)	$ (25,340)
Gain from change in fair value	440	420
Balance at end of period	(27,920)	(24,920)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other (income) expense, net	(4,872)	3,765
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Alternative Investments, Fair Value Disclosure	22,665	23,141	$ 22,539
Other (income) expense, net	$ 83	$ 17