Income Taxes (Narrative) (Details) (USD $)	3 Months Ended						12 Months Ended
	Oct. 31, 2010	Jul. 31, 2010	Apr. 30, 2010	Jan. 31, 2010	Oct. 31, 2009	Jul. 31, 2009	Apr. 30, 2011	Apr. 30, 2010	Apr. 30, 2009	Apr. 30, 2008
Loss from discontinued operations	$ (2,237,000)	$ (3,043,000)	$ (1,604,000)	$ (2,968,000)	$ (2,115,000)	$ (3,017,000)	$ (13,295,000)	$ (9,704,000)	$ (27,382,000)
Loss from discontinued operations, tax benefits							8,700,000	8,000,000	20,300,000
Effective income tax rate discontinuing operations							39.40%	45.10%	42.50%
Deferred tax asset			354,509,000				339,848,000	354,509,000
Capital loss carryovers							375,000,000
Noncurrent deferred tax liability resulting from change in accounting method							81,100,000
Increase in noncurrent deferred tax liability							66,300,000
Balance, end of the year			129,767,000				154,848,000	129,767,000	124,605,000	137,608,000
Unrecognized tax benefits that would impact effective tax rate			106,800,000				117,600,000	106,800,000	107,000,000
Effect of anticipated settlements of audit issues and expiring statutes of limitations							17,000,000
Gross interest and penalties accrued on uncertain tax positions			4,100,000				4,400,000	4,100,000	15,400,000
Total gross interest and penalties accrued			39,700,000				44,100,000	39,700,000	42,400,000
State and Local Jurisdiction [Member]
Deferred tax asset							21,100,000
Valuation allowance							10,300,000
Ameriprise [Member]
Deferred tax asset							147,000,000
Valuation allowance							$ 126,300,000