Goodwill (Schedule of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill, balance at the beginning of the period	$ 74,825	$ 75,509	$ 75,691
Translation adjustment	2,195	(684)	(3,181)
Goodwill acquired	7,741		2,999
Goodwill, balance at the end of the period	84,761	74,825	75,509
Industrial
Goodwill [Roll Forward]
Goodwill, balance at the beginning of the period	56,447	56,293	57,320
Translation adjustment	389	154	(1,027)
Goodwill acquired	4,846		0
Goodwill, balance at the end of the period	61,682	56,447	56,293
Agricultural
Goodwill [Roll Forward]
Goodwill, balance at the beginning of the period	3,489	2,984	695
Translation adjustment	(27)	505	(710)
Goodwill acquired	2,895		2,999
Goodwill, balance at the end of the period	6,357	3,489	2,984
European
Goodwill [Roll Forward]
Goodwill, balance at the beginning of the period	14,889	16,232	17,676
Translation adjustment	1,833	(1,343)	(1,444)
Goodwill acquired	0		0
Goodwill, balance at the end of the period	$ 16,722	$ 14,889	$ 16,232