Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Domestic and foreign components of income (loss) before income taxes are as follows:
Domestic										$ 591	$ (35,100)	$ 9,867
Foreign										3,466	1,564	862
Income (loss) before income taxes	$ 1,831		$ 299	$ 650	$ 1,277	$ 1,606	$ (16,403)	$ 1,789	$ (20,528)	4,057	(33,536)	10,729
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current U.S. federal										(570)	47	2,212
Current Foreign										1,458	1,533	1,085
Current U.S. state and local										116	101	495
Current Total current tax										1,004	1,681	3,792
Deferred tax:
Enactment of the Tax Cuts and Jobs Act		$ 1,700								1,704
Deferred U.S. federal										347	(584)	337
Deferred Foreign										(25)	28	(19)
Deferred U.S. state and local										221	(23)	109
Deferred income taxes										2,247	(579)	427
Total tax	2,250		259	216	526	463	(220)	530	329	3,251	1,102	4,219
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Tax at statutory rate of 34%										1,379	(11,402)	3,648
State tax, net of federal benefit										212	47	409
Non-taxable income										(573)	(495)	(576)
Non-deductible expenses										971	13,465	686
Change in estimate primarily related to foreign taxes										(69)	46	192
Change in estimate primarily related to U.S. federal taxes												178
Tax credits										(289)	(552)	(253)
Enactment of the Tax Cuts and Jobs Act		$ 1,700								1,704
Foreign rate differential										(164)	(46)	69
Other, net										80	39	(134)
Total tax	$ 2,250		$ 259	$ 216	$ 526	$ 463	$ (220)	$ 530	$ 329	$ 3,251	$ 1,102	$ 4,219
Effective income tax rate										80.10%	(3.30%)	39.30%