Convertible Special Stock (Details) - USD ($)	3 Months Ended			6 Months Ended		12 Months Ended
	Feb. 29, 2016	May. 31, 2015	Feb. 28, 2015	Feb. 29, 2016	Feb. 28, 2015	Aug. 31, 2015	May. 04, 2015
Class of Stock [Line Items]
Convertible special stock, shares authorized							125,000
Convertible special stock, dividend rate, percentage							6.00%
Issuances of convertible special stock, gross		$ 125,000,000
Convertible special stock, shares issued							125,000
Convertible special stock, no par value	$ 120,289,000			$ 120,289,000		$ 120,289,000
Payment of financing and stock issuance costs							$ 4,700,000
Convertible special stock, shares converted to common shares				0		0
Convertible special stock dividends	$ 1,875,000		$ 0	$ 3,750,000	$ 0