Shareholders' Deficit (Share Repurchase) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 26, 2019	Dec. 26, 2018	Jun. 27, 2018	Jun. 26, 2019	Jun. 27, 2018
Equity, Class of Treasury Stock [Line Items]
Purchase of treasury stock	$ 29,056		$ 12,658	$ 37,997	$ 28,844
Number of accumulated shares repurchased (in shares)	49,484	47,052		49,484
Share Repurchase Program 2017 [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase, authorized amount (in dollars)	$ 200,000			$ 200,000
Purchase of treasury stock (in shares)				2,000
Purchase of treasury stock				$ 38,000
Remaining shares to be repurchased (in dollars)	$ 90,400			$ 90,400
Number of accumulated shares repurchased (in shares)	6,600			6,600
Value of shares repurchased	$ 109,600			$ 109,600
Accelerated Share Repurchase 2018 [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase, authorized amount (in dollars)		$ 25,000
Purchase of treasury stock (in shares)		1,100		400
Purchase of treasury stock		$ 18,200		$ 6,800
Remaining shares to be repurchased (in dollars)		$ 6,800
Volume-weighted average price				$ 17.04