Goodwill and Intangible Assets (Schedule of Goodwill) (Details) (USD $) In Thousands	12 Months Ended
	Apr. 30, 2011	Apr. 30, 2010	Apr. 30, 2009
Goodwill before impairment losses, beginning balance	$ 857,635	$ 852,418
Accumulated impairment losses, beginning balance	(17,188)	(2,188)
Goodwill, beginning balance	840,447	850,230
Acquisitions	43,993	6,248
Disposals and foreign currency changes	(15,495)	(1,031)
Impairments	(22,700)	(15,000)
Goodwill before impairment losses, ending balance	886,133	857,635
Accumulated impairment losses, ending balance	(39,888)	(17,188)
Goodwill, ending balance	846,245	840,447
Tax Services [Member]
Goodwill before impairment losses, beginning balance	453,884	449,779
Accumulated impairment losses, beginning balance	(2,188)	(2,188)
Goodwill, beginning balance	451,696	447,591
Acquisitions	15,441	5,136
Disposals and foreign currency changes	(10,286)	(1,031)
Impairments	(22,700)		(2,200)
Goodwill before impairment losses, ending balance	459,039	453,884	449,779
Accumulated impairment losses, ending balance	(24,888)	(2,188)	(2,188)
Goodwill, ending balance	434,151	451,696	447,591
Business Services [Member]
Goodwill before impairment losses, beginning balance	403,751	402,639
Accumulated impairment losses, beginning balance	(15,000)
Goodwill, beginning balance	388,751	402,639
Acquisitions	28,552	1,112
Disposals and foreign currency changes	(5,209)
Impairments		(15,000)
Goodwill before impairment losses, ending balance	427,094	403,751
Accumulated impairment losses, ending balance	(15,000)	(15,000)
Goodwill, ending balance	$ 412,094	$ 388,751