Balance Sheet Components - Components (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
RECEIVABLES
Customers	$ 298,118	$ 313,719
Other	6,415	5,182
Total	304,533	318,901
Less allowance for doubtful accounts	6,347	6,709
Total receivables - net	298,186	312,192
INVENTORIES
Raw materials and components parts	182,382	178,805
Work in process	28,761	37,495
Finished goods	82,324	63,695
Total	293,467	279,995
PROPERTY, PLANT AND EQUIPMENT
Land and improvements	32,240	32,100
Buildings and improvements	187,301	189,744
Machinery, equipment and other	397,498	372,804
Office and transportation equipment	95,759	96,350
Construction in progress	24,546	24,328
Total	737,344	715,326
Less accumulated depreciation and amortization	457,028	434,106
Total property, plant and equipment - net	280,316	281,220
ACCRUED EXPENSES
Payroll and related items	77,556	78,944
Management incentive compensation	14,408	25,321
Income taxes payable	9,905	23,844
Insurance	8,240	10,422
Warranty	5,581	5,303
Deferred revenue	17,633	8,055
Lease liability	15,235
Restructuring	6,110	6,170
Liability for uncertain tax positions	890	980
Accrued interest	1,735	1,759
Contingent consideration for acquisition	3,375	0
Other	19,622	26,738
Total accrued expenses	180,290	187,536
OTHER NONCURRENT LIABILITIES
Pension and retiree medical obligations	87,478	80,667
Transition tax payable	11,292	17,127
Liability for uncertain tax positions	3,008	3,183
Deferred revenue	2,129	3,027
Liability for construction of new leased facility	0	11,616
Lease liability	69,928
Contingent consideration for acquisition	0	3,375
Other	23,533	19,219
Total other noncurrent liabilities	$ 197,368	$ 138,214