Stock-based Compensation (Details 1) (Stock Appreciation Rights SARS and Stock Option [Member], USD $)	9 Months Ended
	Nov. 30, 2013
Stock Appreciation Rights SARS and Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments, Number of Shares [Roll Forward]
Outstanding as of February 28, 2013 (shares)	439,863
Granted (shares)	112,381
Exercised (shares)	(135,380)
Forfeited (shares)	0
Outstanding as of May 31, 2013 (shares)	416,864
Exercisable as of May 31, 2013	240,076
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instrument, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding as of February 28, 2013, Weighted Average Exercise Price (usd per share)	$ 19.12
Granted, Weighted Average Exercise Price (usd per share)	$ 45.33
Exercised, Weighted Average Exercise Price (usd per share)	$ 19.08
Forfeited, Weighted Average Exercise Price (usd per share)	$ 0.00
Outstanding at end of the period ended May 31, 2013, Weighted Average Exercise Price (usd per share)	$ 26.23
Exercisable at end of period ended May 31, 2013, Weighted Average Exercise Price (usd per share)	$ 19.85
Weighted average fair value of options and SARs granted during the period ended May 31, 2013 (usd per share)	$ 13.72