Investment in Receivable Portfolios, Net - Summary of Changes in Balance of Investment in Receivable Portfolios (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended			9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2013 AACC Merger [Member]	Sep. 30, 2014 Accrual Basis Portfolios [Member]	Sep. 30, 2013 Accrual Basis Portfolios [Member]	Sep. 30, 2014 Accrual Basis Portfolios [Member]	Sep. 30, 2013 Accrual Basis Portfolios [Member]	Sep. 30, 2014 Cost Recovery Portfolios [Member]	Sep. 30, 2013 Cost Recovery Portfolios [Member]	Sep. 30, 2014 Cost Recovery Portfolios [Member]	Sep. 30, 2013 Cost Recovery Portfolios [Member]	Sep. 30, 2014 Zero Basis Portfolios [Member]	Sep. 30, 2013 Zero Basis Portfolios [Member]	Sep. 30, 2014 Zero Basis Portfolios [Member]	Sep. 30, 2013 Zero Basis Portfolios [Member]	Sep. 30, 2014 Atlantic Credit and Finance, Inc. [Member]	Sep. 30, 2013 Cabot Acquisition [Member]	Mar. 31, 2014 Marlin [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance, beginning of period	$ 1,987,985	$ 1,096,698	$ 1,590,249	$ 873,119		$ 1,978,493	$ 1,090,922	$ 1,585,587	$ 873,119	$ 9,492	$ 5,776	$ 4,662	$ 0	$ 0	$ 0	$ 0	$ 0
Purchases of receivable portfolios	299,509	617,852	992,836	1,099,736	383,400	297,800	616,779	991,127	1,098,663	1,709	1,073	1,709	1,073	0	0	0	0	105,400	559,000	208,500
Transfer of portfolios	0	0	0	0		(11,519)	0	(18,682)	(6,649)	11,519	0	18,682	6,649	0	0	0	0
Gross collections	(407,220)	(379,670)	(1,213,174)	(928,228)		(395,945)	(371,482)	(1,186,431)	(905,751)	(4,056)	(983)	(6,305)	(1,825)	(7,219)	(7,205)	(20,438)	(20,652)
Put-backs and recalls	(1,544)	(997)	(10,770)	(2,787)		(2,817)	(755)	(11,640)	(2,512)	1,278	(242)	875	(273)	(5)	0	(5)	(2)
Foreign currency adjustments	(57,283)	36,372	(23,493)	35,708		(55,865)	36,372	(22,394)	35,708	(1,418)	0	(1,099)	0	0	0	0	0
Revenue recognized	245,982	222,409	725,129	510,436		241,502	218,182	713,656	496,804	0	0	0	0	4,480	4,227	11,473	13,632
Portfolio allowance reversals, net	5,803	2,978	12,455	7,658		3,059	0	3,485	636	0	0	0	0	2,744	2,978	8,970	7,022
Balance, end of period	$ 2,073,232	$ 1,595,642	$ 2,073,232	$ 1,595,642		$ 2,054,708	$ 1,590,018	$ 2,054,708	$ 1,590,018	$ 18,524	$ 5,624	$ 18,524	$ 5,624	$ 0	$ 0	$ 0	$ 0
Revenue as a percentage of collections	60.40%	58.60%	59.80%	55.00%		61.00%	58.70%	60.20%	54.80%	0.00%	0.00%	0.00%	0.00%	62.10%	58.70%	56.10%	66.00%