Stock Repurchase Program (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017	Jan. 31, 2017
Class of Stock Disclosures [Abstract]
Authorized amount					$ 525,000
Remaining authorized repurchase amount	$ 325,000		$ 325,000
Shares repurchased	1,224	0	2,512	0
Total cost of repurchased shares	$ 50,012	$ 0	$ 100,025	$ 0