Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	May 31, 2012 segment		Feb. 29, 2012		Nov. 30, 2011		Aug. 31, 2011		May 31, 2011	Feb. 28, 2011	Nov. 30, 2010	Aug. 31, 2010	May 31, 2012 segment	May 31, 2011	May 31, 2010
Segment Reporting Information [Line Items]
Number of reportable segments	2												2
Revenues	$ 597,032		$ 533,539		$ 530,505		$ 542,771		$ 519,754	$ 456,382	$ 443,526	$ 440,138	$ 2,203,847	$ 1,859,802	$ 1,642,468
Operating income (loss) for segments	9,811	[1]	92,348	[1]	96,580	[1]	108,610	[1]	88,143	78,199	83,143	82,107	307,349	331,594	323,279
Depreciation and amortization													99,099	82,237	68,667
Long-lived assets	1,320,722								1,377,438				1,320,722	1,377,438
United States [Member]
Segment Reporting Information [Line Items]
Revenues													1,234,818	1,031,997	902,844
Long-lived assets	352,419								291,301				352,419	291,301
Canada
Segment Reporting Information [Line Items]
Revenues													332,434	330,872	317,272
Long-lived assets	167,024								181,837				167,024	181,837
Europe [Member]
Segment Reporting Information [Line Items]
Revenues													489,300	359,567	315,023
Long-lived assets	715,512								812,936				715,512	812,936
Asia-Pacific [Member]
Segment Reporting Information [Line Items]
Revenues													147,295	137,366	107,329
Long-lived assets	85,592								91,364				85,592	91,364
Latin America [Member]
Segment Reporting Information [Line Items]
Long-lived assets	175								0				175	0
North America merchant services
Segment Reporting Information [Line Items]
Revenues													1,567,252	1,362,869	1,220,116
Operating income (loss) for segments													281,305	268,233	275,386
Depreciation and amortization													35,479	32,605	26,221
International merchant services
Segment Reporting Information [Line Items]
Revenues													636,595	496,933	422,352
Operating income (loss) for segments													196,137	143,911	113,699
Depreciation and amortization													60,462	48,104	40,564
Corporate [Member]
Segment Reporting Information [Line Items]
Operating income (loss) for segments													(170,093)	(80,550)	(65,806)
Depreciation and amortization													3,158	1,528	519
Discontinued operations [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization													$ 0	$ 0	$ 1,363

[1] Includes processing system intrusion charges of $84.4 million in the quarter ended May 31, 2012.