Segment Reporting - Financial Results by Reportable Segment Reconciled to Consolidated Income Before Income Taxes and Total Assets by Reportable Segment Reconciled to Consolidated Total Assets (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]
Performance Fees Earned in Connection with Equity Method Investment	$ 34.2		$ 34.2
Servicing [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Servicing revenue and fees	5.0	4.7	9.6	9.6
Asset Receivables Management [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Servicing revenue and fees	$ 0.2	$ 0.1	$ 0.3	$ 0.2