Business Combinations - Components of Purchase Price Allocation (Detail) $ in Thousands, £ in Millions		3 Months Ended	9 Months Ended
	Jun. 01, 2015 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 01, 2015 GBP (£)	Dec. 31, 2014 USD ($)
Allocation of purchase price:
Goodwill		$ 940,181	$ 940,181		$ 897,933
Hillesden Securities Ltd (dlc) [Member]
Business Acquisition [Line Items]
Cash paid at acquisition	$ 268,391
Deferred consideration	6,306
Total purchase price	274,697
Allocation of purchase price:
Cash	30,518
Investment in receivable portfolios	215,988
Deferred court costs	760
Property and equipment	1,327
Other assets	2,384
Liabilities assumed	(44,335)
Identifiable intangible assets	3,670
Goodwill	64,385
Total net assets acquired	$ 274,697			£ 180.6
Acquisition and integration costs		100	2,800
Revenue of acquiree recognized since acquisition date		11,700	16,100
Net income of acquiree recognized since acquisition date		$ 2,300	$ 3,800