PARENT COMPANY FINANCIAL STATEMENTS - Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
CONDENSED STATEMENTS OF OPERATIONS [Abstract]
Interest expense	$ 3,828	$ 3,083	$ 8,460	$ 5,862	$ 4,708	$ 1,881	$ 3,282	$ 1,003	$ 462	$ 1,755	$ 1,377	$ 1,278	$ 21,233	$ 10,874	$ 4,872
Other expense													51,694	47,826	45,865
Income tax benefit													29,141	16,324	27,964
Other income													23,167	22,115	17,357
Net income before noncontrolling interest													169,650	165,807	159,354
Net income attributable to parent	$ 33,597	$ 41,835	$ 65,268	$ 27,657	$ 35,906	$ 45,096	$ 54,771	$ 27,842	$ 23,420	$ 22,391	$ 49,251	$ 61,324	168,357	163,615	156,386
Meta Financial
CONDENSED STATEMENTS OF OPERATIONS [Abstract]
Interest expense													2,667	2,538	3,982
Other expense													3,297	1,409	1,062
Total expense													5,964	3,947	5,044
Loss before income taxes and equity in undistributed net income of subsidiaries													(5,964)	(3,947)	(5,044)
Income tax benefit													(1,147)	(967)	(1,029)
Loss before equity in undistributed net income of subsidiaries													(4,817)	(2,980)	(4,015)
Equity in undistributed net income of subsidiaries													172,017	166,738	159,652
Other income													1,157	(143)	749
Net income before noncontrolling interest													173,174	166,595	160,401
Net income attributable to parent													$ 168,357	$ 163,615	$ 156,386