Common Stock Repurchases (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Oct. 31, 2011		Jul. 31, 2011		Apr. 30, 2011		Jan. 31, 2011
Share-Based Compensation Arrangement By Share-Based Payment Award, Options Exercisable [Abstract]
Exercises	20,000		90,000		274,167		88,750
Exercise Price	$ 18.00		$ 18.95		$ 22.03		$ 16.93
Shares Net Settled for Exercise	8,041		38,198		147,748		38,025
Shares With held for Taxes	4,487	[1]	24,183	[1]	59,016	[1]	18,917	[1]
Net Shares to Employee	7,472		27,619		67,403		31,808
Share Price for Withholding	$ 44.77		$ 44.65		$ 40.80		$ 39.51
Tax Withholding (in 000's)	$ 201		$ 1,080		$ 2,408		$ 748

[1] Shares withheld for taxes are treated as a repurchase of shares for accounting purposes but do not count against our stock repurchase program.