Investment in Receivable Portfolios, Net - Additional Information (Detail) (USD $)	3 Months Ended			6 Months Ended
	Mar. 31, 2015	Sep. 30, 2014	Mar. 31, 2014	Jun. 30, 2014
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net [Line Items]
Collection forecast estimated on receivable portfolios		120 months
Income recognized under cost recovery method	$ 0
Purchase price of receivable portfolios	125,154,000		467,565,000
Face value of receivable portfolios	1,000,000,000		4,300,000,000
Purchase cost as a percentage of face value	12.00%		10.90%
Estimated future collections at acquisition for receivable portfolios	197,500,000		1,000,000,000
Revenue recognized, net	264,110,000		237,568,000
Estimate of Zero Basis Cash Flows [Member]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net [Line Items]
Revenue recognized, net	15,571,000		6,511,000
Marlin [Member]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net [Line Items]
Purchase price of receivable portfolios			$ 208,500,000
Minimum [Member]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net [Line Items]
Collection forecast estimated on receivable portfolios				84 months
Maximum [Member]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net [Line Items]
Collection forecast estimated on receivable portfolios				96 months