Accrued Expenses Components of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Salaries and wages	$ 35,162	$ 32,959
Warranty cost	23,116	23,302
Taxes other than income taxes, primarily value added taxes	21,340	19,194
Professional	4,817	4,728
Freight	4,248	5,211
Interest	3,973	3,747
Severance	2,814	2,049
Product liability, current portion	2,472	3,996
Deferred revenue	1,899	1,446
Derivative liabilities (foreign currency forward exchange contracts)	1,865	1,783
Insurance	785	742
Rent	638	672
Marketing	501	356
Supplemental Executive Retirement Program liability	391	391
Other items, principally trade accruals	9,991	9,519
Accrued expenses	$ 114,012	$ 110,095