Revenue Recognition - Accounts Receivable Allowance - (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Apr. 01, 2017	Dec. 31, 2016
Roll forward of the accounts receivable allowance
Balance at beginning of period	$ 4,253	$ 3,648
Increases to reserves	1,688	2,761
Amounts written off	(659)	(2,156)
Effects of foreign currency translation	4
Balance at end of period	$ 5,286	$ 4,253