Stockholders' Equity (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Aug. 31, 2012	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Summary of shares purchased by employees under the stock purchase plan
Shares Purchased	23	50	51	44	45
Purchase Price	$ 24.88	$ 28.08	$ 28.02	$ 26.44	$ 22.67