Business Combinations and Disposals (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended				12 Months Ended
	Jul. 20, 2010	Apr. 30, 2011	Apr. 30, 2010	Apr. 30, 2009	Oct. 14, 2010 2SS Holdings, Inc. [Member]	Apr. 30, 2011 Caturano & Company, Inc. [Member]	Jul. 20, 2010 Caturano & Company, Inc. [Member]	Nov. 03, 2008 Major Independent Franchise Operator [Member]	Apr. 30, 2011 Other Acquisitions [Member]	Apr. 30, 2010 Other Acquisitions [Member]	Apr. 30, 2009 Other Acquisitions [Member]
Total purchase price							$ 40,218,000	$ 279,200,000
Cash paid for acquisition					287,500,000		32,600,000		19,100,000	10,300,000	12,600,000
Cash paid at closing	29,800,000
Time period of deferred purchase price (years)	13
Deferred Compensation, Employee Retention And Performance Bonus Plan Expense						2,600,000
Proceeds from sale of retail tax offices		65,600,000	65,700,000	16,900,000
Gain on sale of retail tax offices		45,100,000	49,000,000	14,900,000
Contingent consideration paid		$ 2,500,000	$ 200,000	$ 1,900,000