Investment in Receivable Portfolios, Net - Summary of Changes in Balance of Investment in Receivable Portfolios (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investment in Receivables Portfolio [Roll Forward]
Balance, beginning of period				$ 2,143,560				$ 1,590,249	$ 2,143,560	$ 1,590,249	$ 873,119
Purchases of receivable portfolios									1,023,722	1,251,360	1,204,779
Transfer of portfolios										0	0
Gross collections	$ (416,577)	$ (421,753)	$ (437,324)	(425,071)	$ (394,323)	$ (407,220)	$ (409,280)	(396,674)	(1,700,725)	(1,607,497)	(1,279,506)
Put-backs and Recalls									(13,297)	(15,707)	(2,629)
Foreign currency adjustments									(85,027)	(67,677)	49,634
Revenue recognized									1,065,673	975,425	732,659
Portfolio (allowance) reversals, net									6,763	17,407	12,193
Balance, end of period	2,440,669				2,143,560				$ 2,440,669	$ 2,143,560	$ 1,590,249
Revenue as a percentage of collections									62.70%	60.70%	57.30%
Accrual Basis Portfolios [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance, beginning of period				2,131,084				1,585,587	$ 2,131,084	$ 1,585,587	$ 873,119
Purchases of receivable portfolios									1,023,722	1,249,651	1,203,706
Transfer of portfolios										(18,682)	(6,649)
Gross collections									(1,587,525)	(1,563,996)	(1,249,625)
Put-backs and Recalls									(13,009)	(15,162)	(2,331)
Foreign currency adjustments									(82,443)	(64,646)	49,634
Revenue recognized									969,227	953,154	715,458
Portfolio (allowance) reversals, net									(5,002)	5,178	2,275
Balance, end of period	2,436,054				2,131,084				$ 2,436,054	$ 2,131,084	$ 1,585,587
Revenue as a percentage of collections									61.10%	60.90%	57.30%
Cost Recovery Portfolios [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance, beginning of period				12,476				4,662	$ 12,476	$ 4,662	$ 0
Purchases of receivable portfolios									0	1,709	1,073
Transfer of portfolios										18,682	6,649
Gross collections									(5,237)	(9,010)	(2,764)
Put-backs and Recalls									(20)	(536)	(296)
Foreign currency adjustments									(2,604)	(3,031)	0
Revenue recognized									0	0	0
Portfolio (allowance) reversals, net									0	0	0
Balance, end of period	4,615				12,476				$ 4,615	$ 12,476	$ 4,662
Revenue as a percentage of collections									0.00%	0.00%	0.00%
Zero Basis Portfolios [Member]
Investment in Receivables Portfolio [Roll Forward]
Balance, beginning of period				$ 0				$ 0	$ 0	$ 0	$ 0
Purchases of receivable portfolios									0	0	0
Transfer of portfolios										0	0
Gross collections									(107,963)	(34,491)	(27,117)
Put-backs and Recalls									(268)	(9)	(2)
Foreign currency adjustments									20	0	0
Revenue recognized									96,446	22,271	17,201
Portfolio (allowance) reversals, net									11,765	12,229	9,918
Balance, end of period	$ 0				$ 0				$ 0	$ 0	$ 0
Revenue as a percentage of collections									89.30%	64.60%	63.40%