Settlement Processing Assets and Obligations (Details) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2014	May 31, 2013
Offsetting Assets [Line Items]
Total	$ 283,414	$ 259,204
Total	(171,563)	(162,558)
Merchant Reserves [Member]
Offsetting Assets [Line Items]
Merchant Reserves	(82,030)	(57,409)
Reserves for processing obligations	(95,717)	(223,314)
Allowance For Operating Losses [Member]
Offsetting Assets [Line Items]
Reserves for processing obligations	(2,104)	(2,318)
Allowance for Trade Receivables [Member]
Offsetting Assets [Line Items]
Reserves for processing obligations	(1,072)	(961)
Interchange Reimbursement [Member]
Offsetting Assets [Line Items]
Settlement processing assets, gross	184,195	70,348
Settlement processing obligations, gross	43,676	200,319
(Liability To) Receivable From Members [Member]
Offsetting Assets [Line Items]
Settlement processing assets, gross	57,670	117,404
Settlement processing obligations, gross	19,229	(27,717)
Receivables From Card Networks [Member]
Offsetting Assets [Line Items]
Settlement processing assets, gross	114,822	126,136
Liability to Merchants [Member]
Offsetting Assets [Line Items]
Settlement processing obligations, gross	(139,820)	(120,875)
Exceptional Items [Member]
Offsetting Assets [Line Items]
Settlement processing assets, gross	8,757	2,725
Settlement processing obligations, gross	$ 4,245	$ 12,308