Debt Obligations - Interest Expense, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 24, 2017	Sep. 30, 2018	Sep. 24, 2017
Debt Disclosure [Abstract]
Interest expense	$ 7,061	$ 6,956	$ 21,078	$ 20,775
Amortization of debt costs and discount on debt	839	801	2,528	2,379
Capitalized interest	(38)	(345)	(412)	(852)
Interest income and other, net	(3,836)	(2,752)	(9,755)	(7,184)
Total interest expense and other, net	$ 4,026	$ 4,660	$ 13,439	$ 15,118