SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Quarterly Financial Information Disclosure [Abstract]
Interest and dividend income	$ 80,222	$ 73,906	$ 85,177	$ 72,891	$ 72,056	$ 69,983	$ 75,669	$ 68,146	$ 68,407	$ 67,406	$ 79,403	$ 77,625	$ 312,196	$ 285,854	$ 292,841
Interest expense	462	1,755	1,377	1,278	1,389	1,508	1,819	2,147	3,894	5,269	11,666	12,974	4,872	6,863	33,803
Net interest income (expense)	79,760	72,151	83,800	71,613	70,667	68,475	73,850	65,999	64,513	62,137	67,737	64,651	307,324	278,991	259,038
Provision for credit losses	(2,648)	(1,302)	32,302	186	8,775	4,612	30,290	6,089	8,980	15,093	37,296	3,407	28,538	49,766	64,776
Noninterest income	43,456	53,994	109,766	86,591	49,542	62,453	113,453	45,455	40,750	41,048	120,513	37,483	293,807	270,904	239,794
Net income attributable to Pathward Financial, Inc.	$ 23,420	$ 22,391	$ 49,251	$ 61,324	$ 15,903	$ 38,701	$ 59,066	$ 28,037	$ 13,158	$ 18,190	$ 52,304	$ 21,068	$ 156,386	$ 141,708	$ 104,720
Earnings per common share
Basic (in dollars per share)	$ 0.81	$ 0.76	$ 1.66	$ 2.00	$ 0.50	$ 1.21	$ 1.84	$ 0.84	$ 0.38	$ 0.53	$ 1.45	$ 0.56	$ 5.26	$ 4.38	$ 2.94
Diluted (in dollars per share)	0.81	0.76	1.66	2.00	0.50	1.21	1.84	0.84	0.38	0.53	1.45	0.56	$ 5.26	$ 4.38	$ 2.94
Dividend declared per share (in dollars per share)	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05	$ 0.05