Goodwill And Intangible Assets (Schedule Of Goodwill) (Details) (USD $) In Thousands	3 Months Ended
	Jul. 31, 2011
Goodwill before impairment losses, beginning balance	$ 886,133
Accumulated impairment losses, beginning balance	(39,888)
Goodwill, beginning balance	846,245
Acquisitions	3,512
Disposals and foreign currency changes	(7,449)
Impairments	(99,697)
Goodwill before impairment losses, ending balance	882,196
Accumulated impairment losses, ending balance	(139,585)
Goodwill, ending balance	742,611
Tax Services [Member]
Goodwill before impairment losses, beginning balance	459,039
Accumulated impairment losses, beginning balance	(24,888)
Goodwill, beginning balance	434,151
Acquisitions	3,478
Disposals and foreign currency changes	112
Impairments
Goodwill before impairment losses, ending balance	462,629
Accumulated impairment losses, ending balance	(24,888)
Goodwill, ending balance	437,741
Business Services [Member]
Goodwill before impairment losses, beginning balance	427,094
Accumulated impairment losses, beginning balance	(15,000)
Goodwill, beginning balance	412,094
Acquisitions	34
Disposals and foreign currency changes	(7,561)
Impairments	(99,697)
Goodwill before impairment losses, ending balance	419,567
Accumulated impairment losses, ending balance	(114,697)
Goodwill, ending balance	$ 304,870