Segment information (Details 2) (Revenue, Geographical concentration risk, Multi-currency processing services)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
APAC | Customer A
Revenue concentration
Concentration risk (as a percent)	62.00%	63.00%	61.00%
APAC | Customer D
Revenue concentration
Concentration risk (as a percent)	12.00%	13.00%	13.00%
North America | Customer E
Revenue concentration
Concentration risk (as a percent)	18.00%	11.00%	24.00%
North America | Customer F
Revenue concentration
Concentration risk (as a percent)	44.00%	54.00%	25.00%
North America | Customer G
Revenue concentration
Concentration risk (as a percent)	11.00%	21.00%	34.00%
CEMEA | Customer C
Revenue concentration
Concentration risk (as a percent)	97.00%	100.00%	82.00%