Accumulated Other Comprehensive Income (Loss) (Reclassifications Out of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 28, 2014	Feb. 28, 2013	Feb. 28, 2014	Feb. 28, 2013
Equity [Abstract]
Amortization of interest rate locks	$ (783)		$ (2,348)
Tax benefit	295		884
Amortization of interest rate locks, net of tax	$ (488)	$ (488)	$ (1,464)	$ (1,464)