Note 10 - Derivative Financial Instruments (Details) - The Loss From Accumulated Other Comprehensive Income (Loss) (“OCI”) Into Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 28, 2014	Feb. 28, 2013	Feb. 28, 2014	Feb. 28, 2013
Losses on cash flow hedges:
Interest expense	$ 21,900	$ 21,952	$ 66,172	$ 68,691
Effective Portion [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Losses on cash flow hedges:
Interest expense	(243)	(245)	(746)	(763)
Ineffective Portion [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Losses on cash flow hedges:
Interest expense	$ (1)	$ (2)	$ (9)	$ (9)