Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for doubtful accounts, beginning of year	$ 6,574	$ 5,556	$ 5,104
Charges to costs and expenses	1,571	2,383	1,699
Write-offs of uncollectible accounts, net of recoveries	(505)	(1,055)	(973)
Business acquisitions and disposals	0	(351)	(148)
Currency translation adjustments	34	41	(126)
Allowance for doubtful accounts, end of year	$ 7,674	$ 6,574	$ 5,556