Shareholders' Equity (Share Repurchase) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 27, 2019	Dec. 26, 2018	Mar. 28, 2018
Equity, Class of Treasury Stock [Line Items]
Purchase of treasury stock	$ 8,941		$ 16,186
Number of accumulated shares repurchased (in shares)	47,948	47,052
Share Repurchase Program 2017 [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase, authorized amount (in dollars)	$ 200,000
Purchase of treasury stock (in shares)	500
Purchase of treasury stock	$ 8,900
Remaining shares to be repurchased (in dollars)	$ 119,500
Number of accumulated shares repurchased (in shares)	5,100
Value of shares repurchased	$ 80,500
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)	400	1,100
Purchase of treasury stock	$ 6,800	$ 18,200
Remaining shares to be repurchased (in dollars)		$ 6,800
Volume-weighted average price	$ 17.04