Segment information (Details 2) (Revenue, Geographical concentration risk, Multi-currency processing services)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
APAC | Customer A
Revenue concentration
Concentration risk (as a percent)	66.00%	63.00%
APAC | Customer E
Revenue concentration
Concentration risk (as a percent)		13.00%
North America | Customer F
Revenue concentration
Concentration risk (as a percent)	28.00%	16.00%
North America | Customer G
Revenue concentration
Concentration risk (as a percent)	36.00%	53.00%
North America | Customer H
Revenue concentration
Concentration risk (as a percent)		12.00%
CEMEA | Customer C
Revenue concentration
Concentration risk (as a percent)	79.00%	100.00%
CEMEA | Customer I
Revenue concentration
Concentration risk (as a percent)	21.00%