Investment in Receivable Portfolios, Net - Summary of Accretable Yield and an Estimate of Zero Basis Future Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2015	Sep. 30, 2014
Investment in Receivables Portfolio [Roll Forward]
Balance at beginning of period	$ 3,332,242	$ 3,041,631	$ 3,059,713	$ 2,910,986	$ 2,854,453	$ 2,399,936	$ 3,059,713	$ 2,399,936
Revenue recognized, net	(265,523)	(270,301)	(264,110)	(251,785)	(248,231)	(237,568)	(799,934)	(737,584)
Net additions on existing portfolios	114,370	165,880	160,336	215,806	86,717	100,880
Additions for current purchases, net	149,255	395,032	85,692	179,604	218,047	591,205
Balance at end of period	3,330,344	3,332,242	3,041,631	3,054,611	2,910,986	2,854,453	3,330,344	3,054,611
Accretable Yield [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance at beginning of period	3,194,104	2,951,203	2,993,321	2,901,050	2,843,944	2,391,471	2,993,321	2,391,471
Revenue recognized, net	(233,680)	(243,425)	(248,539)	(244,561)	(241,523)	(231,057)
Net additions on existing portfolios	(3,548)	91,294	120,729	161,622	80,582	92,325
Additions for current purchases, net	149,255	395,032	85,692	179,604	218,047	591,205
Balance at end of period	3,106,131	3,194,104	2,951,203	2,997,715	2,901,050	2,843,944	3,106,131	2,997,715
Estimate of Zero Basis Cash Flows [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance at beginning of period	138,138	90,428	66,392	9,936	10,509	8,465	66,392	8,465
Revenue recognized, net	(31,843)	(26,876)	(15,571)	(7,224)	(6,708)	(6,511)	(74,300)	(20,400)
Net additions on existing portfolios	117,918	74,586	39,607	54,184	6,135	8,555
Additions for current purchases, net	0	0	0	0	0	0
Balance at end of period	$ 224,213	$ 138,138	$ 90,428	$ 56,896	$ 9,936	$ 10,509	$ 224,213	$ 56,896