Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jan. 01, 2018
Payables and Accruals [Abstract]
Payroll and related items	$ 68,586	$ 78,944
Management incentive compensation	10,441	25,321
Income taxes payable	12,500	23,844
Insurance	9,513	10,422
Warranty	5,284	5,303
Deferred revenue	11,861	8,055	$ 8,055
Lease liability	12,973	0
Restructuring	3,903	6,170
Liability for uncertain tax positions	830	980
Accrued interest	1,569	1,759
Other	25,378	26,738
Total accrued expenses	$ 162,838	$ 187,536