Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
Payables and Accruals [Abstract]
Payroll and related items	$ 60,351	$ 78,944
Management incentive compensation	6,340	25,321
Income taxes payable	30,892	23,844
Insurance	8,802	10,422
Warranty	5,230	5,303
Deferred revenue	12,392	8,055	$ 8,055
Current lease liabilities	13,194	0
Restructuring	4,026	6,170
Liability for uncertain tax positions	980	980
Accrued interest	10,434	1,759
Other	25,557	26,738
Total accrued expenses	$ 178,198	$ 187,536