Acquisition Consideration (Details 2) (USD $) In Thousands, unless otherwise specified	0 Months Ended	12 Months Ended
	May 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Contingent consideration
Change in fair value of acquisition-related contingent consideration		$ 0	$ 0	$ 3,222
Segmenta | Contingent consideration
Contingent consideration
Balance at the beginning of the period		6,986	6,476	5,062
Change in fair value of acquisition-related contingent consideration				3,222
Interest expense accretion		176	396	676
Payments	(7,100)	(7,065)		(2,080)
Foreign exchange rate changes		(97)	114	(404)
Balance at the end of the period		$ 0	$ 6,986	$ 6,476