Note 11 - Derivative Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2015	Sep. 30, 2014
Interest Expense [Member]
Note 11 - Derivative Financial Instruments (Details) [Line Items]
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred	$ (0.5)
Interest Rate Swap [Member]
Note 11 - Derivative Financial Instruments (Details) [Line Items]
Derivative, Amount of Hedged Item	$ 155.0	$ 240.0
Interest Rate Swap [Member] | London Interbank Offered Rate (LIBOR) [Member]
Note 11 - Derivative Financial Instruments (Details) [Line Items]
Derivative, Lower Fixed Interest Rate Range	1.25%
Derivative, Average Fixed Interest Rate	1.77%	1.67%
Interest Rate Swap [Member] | Effective October 1, 2014 through September 30, 2015 [Member]
Note 11 - Derivative Financial Instruments (Details) [Line Items]
Derivative, Notional Amount	$ 155.0
Interest Rate Swap [Member] | Effective October 1, 2014 through September 30, 2015 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Note 11 - Derivative Financial Instruments (Details) [Line Items]
Derivative, Average Fixed Interest Rate	1.77%
Interest Rate Swap [Member] | Effective October 1, 2015 through September 30, 2016 [Member]
Note 11 - Derivative Financial Instruments (Details) [Line Items]
Derivative, Notional Amount	$ 70.0
Interest Rate Swap [Member] | Effective October 1, 2015 through September 30, 2016 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Note 11 - Derivative Financial Instruments (Details) [Line Items]
Derivative, Average Fixed Interest Rate	1.91%