Commitments and Contingencies - Narrative (Detail)			3 Months Ended	12 Months Ended
	Oct. 14, 2014 USD ($)	May. 19, 2008 subsidiary	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) class_action	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	May. 11, 2011 class_action	Dec. 17, 2010 class_action
Loss Contingencies [Line Items]
Number of class actions | class_action				4			2	2
Rent expense				$ 19,400,000	$ 23,000,000	$ 12,000,000
Purchase price of receivable portfolios				1,800,000,000
Purchase price				297,200,000
Purchase commitments in past one year				0
Estimated fair value, liability				0
Settlement fund				2,000,000
Debt forgiveness allocation				$ 13,000,000
Brent v Midland Credit Management [Member]
Loss Contingencies [Line Items]
Number of defendant subsidiaries | subsidiary		2
Class action, damages paid	$ 5,200,000
Class action, damages awarded, maximum	$ 5,700,000
Consent Order, Consumer Finance Protection Bureau [Member]
Loss Contingencies [Line Items]
After-tax expense related to settlement			$ 43,000,000