Accumulated Other Comprehensive Income (Loss) (Changes in Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Nov. 30, 2013	Aug. 31, 2013	Nov. 30, 2012	Nov. 30, 2013	Nov. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 37,951	$ 38,123		$ 38,123
Other comprehensive income (loss) before reclassifications	1,847	(660)
Amounts reclassified from accumulated other comprehensive income (loss)	488	488
Other comprehensive income	2,335	(172)	2,153	2,163	9,505
Ending balance	40,286	37,951		40,286
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	50,666	51,312		51,312
Other comprehensive income (loss) before reclassifications	2,040	(646)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Other comprehensive income	2,040	(646)
Ending balance	52,706	50,666		52,706
Unrealized Loss on Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(13,851)	(14,339)		(14,339)
Other comprehensive income (loss) before reclassifications	(189)	0
Amounts reclassified from accumulated other comprehensive income (loss)	488	488
Other comprehensive income	299	488
Ending balance	(13,552)	(13,851)		(13,552)
Other
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1,136	1,150		1,150
Other comprehensive income (loss) before reclassifications	(4)	(14)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Other comprehensive income	(4)	(14)
Ending balance	$ 1,132	$ 1,136		$ 1,132