Acquisition Consideration (Details) (USD $)	0 Months Ended	12 Months Ended
	May 31, 2013	Dec. 31, 2013	Dec. 31, 2011
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
2008 acquisition
Business Acquisition [Line Items]
Additional consideration			$ 900,000