Significant Client Agreements (Details)	12 Months Ended
	Dec. 31, 2012
Concentration Risk [Line Items]
Initial term	3 years
Number of renewals	1
Renewal term	2 years
Resolution period following breach of contract	30 days
Without Breach of Contract
Concentration Risk [Line Items]
Renewal term	1 year
Written notice of contract termination period	90 days