Accounts Receivable (Details) - SEC Schedule, 12-09, Allowance, Credit Loss [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance for doubtful accounts, beginning of year	$ 7,630	$ 6,457	$ 6,853
Charges to costs and expenses	879	2,303	1,460
Write-offs of uncollectible accounts, net of recoveries	(3,985)	(1,505)	(1,661)
Business acquisitions and disposals	(593)	0	0
Currency translation adjustments	353	375	(195)
Allowance for doubtful accounts, end of year	$ 4,284	$ 7,630	$ 6,457