Investment in Receivable Portfolios, Net - Summary of Accretable Yield and an Estimate of Zero Basis Future Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended						9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2014	Sep. 30, 2013
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net [Line Items]
Purchase price of receivable portfolios	$ 299,509			$ 617,852			$ 992,836	$ 1,099,736
Investment in Receivables Portfolio [Roll Forward]
Balance at beginning of period	2,910,986	2,854,453	2,399,936	1,644,213	1,109,130	1,002,310	2,399,936	1,002,310
Revenue recognized, net	(251,785)	(248,231)	(237,568)	(225,387)	(152,024)	(140,683)	(737,584)	(518,094)
Net additions on existing portfolios	215,806	86,717	100,880	32,149	41,242	180,695
Additions for current purchases	179,604	218,047	591,205	975,380	645,865	66,808
Balance at end of period	3,054,611	2,910,986	2,854,453	2,426,355	1,644,213	1,109,130	3,054,611	2,426,355
Accretable Yield [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance at beginning of period	2,901,050	2,843,944	2,391,471	1,622,451	1,090,314	984,944	2,391,471	984,944
Revenue recognized, net	(244,561)	(241,523)	(231,057)	(218,182)	(144,186)	(135,072)
Net additions on existing portfolios	161,622	80,582	92,325	29,101	30,458	173,634
Additions for current purchases	179,604	218,047	591,205	975,380	645,865	66,808
Balance at end of period	2,997,715	2,901,050	2,843,944	2,408,750	1,622,451	1,090,314	2,997,715	2,408,750
Estimate of Zero Basis Cash Flows [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance at beginning of period	9,936	10,509	8,465	21,762	18,816	17,366	8,465	17,366
Revenue recognized, net	(7,224)	(6,708)	(6,511)	(7,205)	(7,838)	(5,611)
Net additions on existing portfolios	54,184	6,135	8,555	3,048	10,784	7,061
Additions for current purchases	0	0	0	0	0	0
Balance at end of period	56,896	9,936	10,509	17,605	21,762	18,816	56,896	17,605
AACC Merger [Member]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net [Line Items]
Purchase price of receivable portfolios					$ 383,400