SEGMENT REPORTING - Summary of Financial Information by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Consolidated revenue	$ 209,280	$ 182,003	$ 593,524	$ 645,318
Consolidated net revenue	138,562	127,253	441,496	426,339
Consolidated gross margin	73,924	63,570	260,587	239,768
Consolidated operating income	(55,414)	12,059	117,454	72,157
Consolidated expenditures for long-lived assets	7,486	2,340	15,351	7,565
Total gross loans receivable	882,356		882,356		$ 553,722
U.S.
Segment Reporting Information [Line Items]
Consolidated revenue	131,674	132,848	386,960	491,936
Consolidated net revenue	83,244	89,363	278,852	320,880
Consolidated gross margin	39,228	43,384	157,614	187,784
Consolidated operating income	(62,099)	(696)	75,909	44,587
Consolidated expenditures for long-lived assets	4,402	2,273	9,226	6,801
Total gross loans receivable	189,183		189,183		223,451
Canada Direct Lending
Segment Reporting Information [Line Items]
Consolidated revenue	66,190	49,155	186,510	153,382
Consolidated net revenue	52,187	37,890	154,717	105,459
Consolidated gross margin	32,188	20,186	96,271	51,984
Consolidated operating income	23,744	12,755	71,334	27,570
Consolidated expenditures for long-lived assets	481	67	991	764
Total gross loans receivable	390,824		390,824		330,271
Canada POS Lending
Segment Reporting Information [Line Items]
Consolidated revenue	11,416	0	20,054	0
Consolidated net revenue	3,131	0	7,927	0
Consolidated gross margin	2,508	0	6,702	0
Consolidated operating income	(17,059)	0	(29,789)	0
Consolidated expenditures for long-lived assets	2,603	$ 0	5,134	$ 0
Total gross loans receivable	$ 302,349		$ 302,349		$ 0