Valuation and Qualifying Accounts (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 receivable, period start	$ 21,512	$ 14,787	$ 14,924
Additions-charged to expense	7,007	9,201	5,046
Amounts written off	(6,068)	(2,889)	(6,058)
Other (primarily changes in foreign currency exchange rates)	(372)	413	875
Allowance for doubtful accounts receivable, period end	$ 22,079	$ 21,512	$ 14,787