Fair Value of Financial Instruments, Significant Unobservable Inputs Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2016	Sep. 27, 2015	Sep. 25, 2016	Sep. 27, 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			900	560
Balance at end of period	$ (27,460)	$ (24,780)	(27,460)	(24,780)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other (income) expense, net	6,584	4,463	5,460	9,870
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	23,490	22,834	23,490	22,834	$ 22,539
Other (income) expense, net	$ 440	$ (176)	$ 922	$ (246)