Accrued Product Warranties (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Movement in Standard Product Warranty Accrual [Roll Forward]
Accrued product warranties, beginning of year	$ 19,530	$ 17,492	$ 20,845	$ 16,514
Amounts paid for warranty services	(3,790)	(3,624)	(12,781)	(13,221)
Warranty provisions for products sold	3,294	5,099	10,785	15,658
Currency translation adjustments and other	90	1,025	275	1,041
Accrued product warranties, end of year	19,124	19,992	19,124	19,992
Current accrued product warranties, end of year	16,193	16,759	16,193	16,759	$ 17,476
Long-term accrued product warranties, end of ear	$ 2,931	$ 3,233	$ 2,931	$ 3,233