Investment in Receivable Portfolios, Net - Summary of Changes in Balance of Investment in Receivable Portfolios (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Investment in Receivables Portfolio [Roll Forward]
Balance, beginning of period	$ 2,351,767	$ 1,987,985	$ 2,143,560	$ 1,590,249
Purchases of receivable portfolios	187,180	299,509	731,114	992,836
Transfer of portfolios		0		0
Gross collections	(421,753)	(407,220)	(1,284,148)	(1,213,174)
Put-backs and Recalls	(5,715)	(1,544)	(9,901)	(10,770)
Foreign currency adjustments	(53,778)	(57,283)	(57,335)	(23,493)
Revenue recognized	268,784	245,982	795,976	725,129
Portfolio (allowance) reversals, net	(3,261)	5,803	3,958	12,455
Balance, end of period	$ 2,323,224	$ 2,073,232	$ 2,323,224	$ 2,073,232
Revenue as a percentage of collections	63.70%	60.40%	62.00%	59.80%
Portfolio allowance	$ 71,715	$ 80,625	$ 71,715	$ 80,625	$ 68,454	$ 75,673	$ 86,428	$ 93,080
Consent order, Consumer Finance Protection Bureau [Member]
Investment in Receivables Portfolio [Roll Forward]
Portfolio allowance	8,300		8,300
Hillesden Securities Ltd (dlc) [Member]
Investment in Receivables Portfolio [Roll Forward]
Investment in receivable portfolios	216,000		216,000
Marlin [Member]
Investment in Receivables Portfolio [Roll Forward]
Investment in receivable portfolios	208,500		208,500
Atlantic Credit and Finance, Inc. [Member]
Investment in Receivables Portfolio [Roll Forward]
Investment in receivable portfolios	105,400		105,400
Accrual Basis Portfolios [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance, beginning of period	2,343,864	1,978,493	2,131,084	1,585,587
Purchases of receivable portfolios	187,180	297,800	731,114	991,127
Transfer of portfolios		(11,519)		(18,682)
Gross collections	(388,822)	(395,945)	(1,205,717)	(1,186,431)
Put-backs and Recalls	(5,677)	(1,530)	(9,652)	(10,353)
Foreign currency adjustments	(52,505)	(55,869)	(54,753)	(22,398)
Revenue recognized	240,039	241,502	731,196	713,656
Portfolio (allowance) reversals, net	(6,358)	3,059	(5,551)	3,485
Balance, end of period	$ 2,317,721	$ 2,055,991	$ 2,317,721	$ 2,055,991
Revenue as a percentage of collections	61.70%	61.00%	60.60%	60.20%
Cost Recovery Portfolios [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance, beginning of period	$ 7,903	$ 9,492	$ 12,476	$ 4,662
Purchases of receivable portfolios	0	1,709	0	1,709
Transfer of portfolios		11,519		18,682
Gross collections	(1,126)	(4,056)	(4,351)	(6,305)
Put-backs and Recalls	(1)	(9)	(20)	(412)
Foreign currency adjustments	(1,273)	(1,414)	(2,602)	(1,095)
Revenue recognized	0	0	0	0
Portfolio (allowance) reversals, net	0	0	0	0
Balance, end of period	$ 5,503	$ 17,241	$ 5,503	$ 17,241
Revenue as a percentage of collections	0.00%	0.00%	0.00%	0.00%
Zero Basis Portfolios [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance, beginning of period	$ 0	$ 0	$ 0	$ 0
Purchases of receivable portfolios	0	0	0	0
Transfer of portfolios		0		0
Gross collections	(31,805)	(7,219)	(74,080)	(20,438)
Put-backs and Recalls	(37)	(5)	(229)	(5)
Foreign currency adjustments	0	0	20	0
Revenue recognized	28,745	4,480	64,780	11,473
Portfolio (allowance) reversals, net	3,097	2,744	9,509	8,970
Balance, end of period	$ 0	$ 0	$ 0	$ 0
Revenue as a percentage of collections	90.40%	62.10%	87.40%	56.10%