Credit Facility (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 29, 2018	Jun. 29, 2018	May 09, 2016	Feb. 28, 2012
Revolving line of credit facility [Member]
Line of Credit Facility [Line Items]
Borrowing capacity under credit facility			$ 45,000,000	$ 20,000,000
Additional borrowing capacity			$ 25,000,000
Maturity date		May 09, 2021
Pledge of capital stock to U.S. subsidiaries		100.00%
Pledge of capital stock to direct foreign subsidiaries		66.00%
Payment of principal	$ 5,500,000	$ 5,500,000
Outstanding balance	$ 13,500,000	$ 13,500,000
Interest rate	3.50%	3.50%
Revolving line of credit facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Margin percentage base rate		1.50%
Revolving line of credit facility [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Margin percentage base rate		0.75%
Term Loan [Member]
Line of Credit Facility [Line Items]
Borrowing capacity under credit facility				$ 47,000,000
Term of debt		5 years