Revenue Recognition (Income Statement Impact) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jul. 02, 2017	Jul. 01, 2018	Jul. 02, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	$ 366,820	$ 330,723	$ 711,793	$ 654,380
Cost of revenue	257,648	238,787	498,116	465,512
Gross profit	109,172	91,936	213,677	188,868
Provision for income taxes	4,368	5,376	6,761	12,911
Net income (loss)	(5,230)	$ 14,582	360	$ 30,576
Adjustments | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	1,423		3,696
Cost of revenue	243		446
Gross profit	1,180		3,250
Provision for income taxes	406		763
Net income (loss)	774		2,487
Balance without adoption of ASC 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	368,243		715,489
Cost of revenue	257,891		498,562
Gross profit	110,352		216,927
Provision for income taxes	4,774		7,524
Net income (loss)	$ (4,456)		$ 2,847