Segment Information (Details) (USD $)	3 Months Ended
	Aug. 31, 2014 segment		Aug. 31, 2013
Segment Reporting Information [Line Items]
Number of reportable segments	2
Revenues	$ 704,895,000		$ 629,685,000
Operating income (loss) for segments	124,398,000		107,384,000
Depreciation and amortization	34,566,000		28,374,000
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	704,895,000		629,685,000
Corporate [Member]
Segment Reporting Information [Line Items]
Operating income (loss) for segments	(27,141,000)		(23,856,000)
Depreciation and amortization	1,600,000		1,576,000
North America merchant services [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	504,007,000		450,505,000
Operating income (loss) for segments	77,937,000		69,699,000
Depreciation and amortization	20,476,000		13,455,000
International merchant services [member]
Segment Reporting Information [Line Items]
Gain (Loss) on Disposition of Assets	2,900,000
International merchant services [member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	200,888,000		179,180,000
Operating income (loss) for segments	73,602,000	[1]	61,541,000	[1]
Depreciation and amortization	12,490,000		13,343,000
United States [Member] | North America merchant services [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	414,042,000		363,833,000
Canada [member] | North America merchant services [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	89,965,000		86,672,000
Europe [Member] | International merchant services [member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	162,787,000		143,188,000
Asia-Pacific [Member] | International merchant services [member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	$ 38,101,000		$ 35,992,000

[1] (1) During the three months ended August 31, 2014, operating income for the International merchant services segment includes a $2.9 million gain on the sale of a component of our Russia business that leased automated teller machines to our sponsor bank in Russia. The gain is presented in the “Sales, general and administrative” line in the Consolidated Statements of Income.