Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Dec. 30, 2017
Disclosure Accrued Expenses [Abstract]
Accrued payroll and related expenses	$ 68,064		$ 67,935
Standard Product Warranty Accrual, Current	59,667		52,834
Accrued warranty	59,667		52,834
Contract with Customer, Liability	69,746	$ 47,647	31,069
Product Liability Contingency, Loss Exposure in Excess of Accrual, High Estimate	5,459		6,068
Accured Restructuring Liabilities, Current	1,597		1,715
Accrued customer rebates	32,184		48,590
Accrued Product Liability And Workers Compensation Liability Current	11,859		11,976
Accrued agent commission	12,221		11,035
Accrued professional services	18,004		18,250
Sales and Excise Tax Payable, Current	15,831		20,881
Other accrued expenses	66,869		51,818
Accrued expenses	$ 361,501		$ 322,171