Acquisitions - Additional Information (Detail)		12 Months Ended		1 Months Ended
	Dec. 31, 2011 USD ($)	Dec. 31, 2011 New Senior Secured Credit Facilities USD ($)	Dec. 31, 2011 S1 Corporation USD ($)	Feb. 10, 2012 S1 Corporation Acquisition USD ($)	Dec. 31, 2011 ISD Corporation USD ($)	Mar. 18, 2011 ISD Corporation	Dec. 31, 2009 Euronet Essentis Limited USD ($)	Dec. 31, 2009 Euronet Essentis Limited GBP (£)
Schedule of Business Acquisitions, Purchase Price Allocation [Line Items]
Acquisition cash paid				$ 360,000,000
Acquisition transaction paid in shares				5,800,000
Aggregate purchase price				565,000,000
Purchase price, per share				$ 10.39
Acquisition transaction, cash exchanged per S1 share				$ 10.00
Acquisition transaction, Company's stock exchanged per S1 share				0.3148
Proration of exchange percentage, S1 share for the Company's shares				33.80%
Proration of exchange percentage, S1 share for cash				66.20%
Share price used to calculate cash payment for fractional shares				$ 34.14
Effective date of acquisition				2012-02-13
Acquisition transaction paid in cash	65,000,000
Proceeds from senior bank financing arranged for business acquisition		295,000,000
Costs related to acquisition			6,700,000
Percentage Of ownership interests						100.00%
Net assets acquired					19,225,000		6,574,000	3,900,000
Cash					$ 2,375,000