Accounts Receivable (Details) (Allowance for Doubtful Accounts [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for doubtful accounts, beginning of year	$ 7,674	$ 6,574	$ 5,556
Charges to costs and expenses	1,723	1,571	2,383
Write-offs of uncollectible accounts, net of recoveries	(961)	(505)	(1,055)
Business acquisitions and disposals	0	0	(351)
Currency translation adjustments	(422)	34	41
Allowance for doubtful accounts, end of year	$ 8,014	$ 7,674	$ 6,574