Acquisitions (Details) (USD $)	1 Months Ended	0 Months Ended	12 Months Ended
	Apr. 30, 2014	May 31, 2013	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2014	Dec. 31, 2012
Business Acquisition [Line Items]
Goodwill			$ 281,714,000		$ 267,587,000	$ 276,599,000
Denmark Acquisition
Business Acquisition [Line Items]
Payments to acquire businesses	800,000
Business combination, consideration transferred, future royalty payments	1,100,000
Business combination, recognized identifiable assets acquired and liabilities assumed, intangible assets, other than goodwill	1,400,000
Goodwill	1,300,000
Business combination, recognized identifiable assets acquired and liabilities assumed, current liabilities	800,000
Segmenta | Contingent consideration
Business Acquisition [Line Items]
Acquisition-related contingent consideration				10,000,000
Additional consideration		$ 7,100,000	$ 7,065,000	$ 2,080,000