LOANS RECEIVABLE AND REVENUE - CSO Guarantee Liability (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Guarantor Obligations [Roll Forward]
Balance, beginning of period	$ 10,412	$ 19,783	$ 17,795	$ 17,052
Charge-offs	(34,010)	(35,680)	(76,948)	(68,311)
Recoveries	8,126	7,025	20,271	21,010
Net charge-offs	(25,884)	(28,655)	(56,677)	(47,301)
Provision for losses	27,091	24,454	50,501	45,831
Balance, end of period	11,619	15,582	11,619	15,582
Consumer Portfolio Segment | Single-Pay
Guarantor Obligations [Roll Forward]
Balance, beginning of period		14		274
Charge-offs		(373)		(1,886)
Recoveries		354		1,102
Net charge-offs		(19)		(784)
Provision for losses		5		510
Balance, end of period		0		0
Consumer Portfolio Segment | Unsecured Installment
Guarantor Obligations [Roll Forward]
Balance, beginning of period	9,886	18,482	17,073	15,630
Charge-offs	(33,017)	(33,166)	(74,736)	(61,122)
Recoveries	7,350	5,857	18,326	16,725
Net charge-offs	(25,667)	(27,309)	(56,410)	(44,397)
Provision for losses	26,974	23,575	50,530	43,515
Balance, end of period	11,193	14,748	11,193	14,748
Consumer Portfolio Segment | Secured Installment
Guarantor Obligations [Roll Forward]
Balance, beginning of period	526	1,287	722	1,148
Charge-offs	(993)	(2,141)	(2,212)	(5,303)
Recoveries	776	814	1,945	3,183
Net charge-offs	(217)	(1,327)	(267)	(2,120)
Provision for losses	117	874	(29)	1,806
Balance, end of period	$ 426	$ 834	$ 426	$ 834