EARNINGS PER COMMON SHARE ("EPS") (Details) - USD ($) $ / shares in Units, $ 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
Basic income per common share:
Net income attributable to Pathward Financial, Inc.	$ 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
Dividends and undistributed earnings allocated to participating securities													(1,542)	(2,453)	(2,565)
Basic net earnings available to common stockholders													166,815	161,162	153,821
Undistributed earnings allocated to nonvested restricted stockholders													1,495	2,372	2,468
Reallocation of undistributed earnings to nonvested restricted stockholders													(1,493)	(2,364)	(2,468)
Diluted net earnings available to common stockholders													$ 166,817	$ 161,170	$ 153,821
Weighted average common shares outstanding (in shares)													25,169,937	26,833,079	29,227,071
Effect of dilutive securities
Total effect of dilutive securities (in shares)													31,813	92,527	5,176
Total weighted average diluted common shares outstanding (in shares)													25,201,750	26,925,606	29,232,247
Net earnings per common share:
Basic earnings per common share (in dollars per share)	$ 1.35	$ 1.66	$ 2.56	$ 1.06	$ 1.37	$ 1.69	$ 1.99	$ 0.98	$ 0.81	$ 0.76	$ 1.66	$ 2.00	$ 6.63	$ 6.01	$ 5.26
Diluted earnings per common share (in dollars per share)	$ 1.35	$ 1.66	$ 2.56	$ 1.06	$ 1.36	$ 1.68	$ 1.99	$ 0.98	$ 0.81	$ 0.76	$ 1.66	$ 2.00	$ 6.62	$ 5.99	$ 5.26
Weighted average shares of nonvested restricted stock, antidilutive (in shares)													232,601	408,477	487,476
Performance share units
Effect of dilutive securities
Performance share units (in shares)													31,813	92,527	5,176