Accumulated Other Comprehensive Income (Loss) (Changes in Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2013	Aug. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 38,123
Other comprehensive loss before reclassifications	(660)
Amounts reclassified from accumulated other comprehensive loss	488
Other comprehensive (loss) income	(172)	7,352
Ending balance	37,951
Foreign Currency [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	51,312
Other comprehensive loss before reclassifications	(646)
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive (loss) income	(646)
Ending balance	50,666
Unrealized Loss on Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(14,339)
Other comprehensive loss before reclassifications	0
Amounts reclassified from accumulated other comprehensive loss	488
Other comprehensive (loss) income	488
Ending balance	(13,851)
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1,150
Other comprehensive loss before reclassifications	(14)
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive (loss) income	(14)
Ending balance	$ 1,136