Other Expense (Income) (Summary of other expense (income)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Nonoperating Income (Expense) [Abstract]
Foreign currency losses	$ 8,395	$ 1,099	$ 9,295
Release of indemnification asset	4,459	5,371	11,180
All other, net	(7,649)	(8,199)	(2,856)
Total other expense (income)	$ (5,205)	$ 1,729	$ (17,619)