Discontinued Operations (Narrative) (Detail) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	1 Months Ended	3 Months Ended								12 Months Ended
	Jun. 05, 2012 Year	Oct. 31, 2011	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2012 Year	Jun. 30, 2011	Jun. 30, 2010	Jun. 25, 2010	May 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Date of sale on business disposal contracts			June 25, 2010								June 25, 2010
Term of subordinated note from PWI, in years											5
Subordinated note receivable due to disposal of discontinued operations			$ 20.6								$ 20.6
Spread over LIBOR (basis points)			0.0550								0.0550
Number of PWI common shares received in connection with disposal of discontinued operations			2,455,627								2,455,627
Percentage of common shares received compared to the total number of common shares															9.50%
Closing price of common stock at completion of sale														$ 5.95
Master services agreement	10										11
Expiration date on agreement											December 2022
Annual revenues under outsourcing services agreement			800.3	547.0	479.8	476.4	776.1	527.1	442.3	421.4	2,303.5	2,166.9	2,209.2
Additional revenue due to outsourcing support services											8.0
Consideration for additional services		7.0
Fee shortfall reimbursement threshold											8.0
Fee shortfall reimbursement maximum											7.0
Outstanding common stock, percentage			9.90%								9.90%
Transition period											24 months
Retain claims under Outsourcing Services Agreement against PFSC			20								20
Deferred Costs			47.2								47.2
Credit Penson fees											15.1
Penson Worldwide, Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Annual revenues under outsourcing services agreement											50.0
Ridge Clearing & Outsourcing Solutions, Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate purchase price on sale of contracts														$ 35.2