Segment information (Details 2) (Revenue, Geographical concentration risk, Multi-currency processing services)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
APAC | Customer A
Revenue concentration
Concentration risk (as a percent)	64.00%	61.00%	64.00%	62.00%
APAC | Customer J
Revenue concentration
Concentration risk (as a percent)		12.00%		13.00%
North America | Customer E
Revenue concentration
Concentration risk (as a percent)	24.00%	19.00%	27.00%	17.00%
North America | Customer F
Revenue concentration
Concentration risk (as a percent)	32.00%	45.00%	31.00%	46.00%
North America | Customer G
Revenue concentration
Concentration risk (as a percent)	11.00%	10.00%	10.00%	11.00%
North America | Customer H
Revenue concentration
Concentration risk (as a percent)	11.00%
CEMEA | Customer C
Revenue concentration
Concentration risk (as a percent)	67.00%	97.00%	75.00%	99.00%
CEMEA | Customer I
Revenue concentration
Concentration risk (as a percent)	33.00%		25.00%