EARNINGS PER COMMON SHARE ("EPS") (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	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, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Basic income per common share:
Net income attributable to Pathward Financial, Inc.	$ 35,906	$ 45,096	$ 54,771	$ 27,842	$ 23,420	$ 22,391	$ 49,251	$ 61,324	$ 15,903	$ 38,701	$ 59,066	$ 28,037	$ 163,615	$ 156,386	$ 141,708
Dividends and undistributed earnings allocated to participating securities													(2,453)	(2,565)	(2,698)
Basic net earnings available to common stockholders													161,162	153,821	139,010
Undistributed earnings allocated to nonvested restricted stockholders													2,372	2,468	2,575
Reallocation of undistributed earnings to nonvested restricted stockholders													(2,364)	(2,468)	(2,573)
Diluted net earnings available to common stockholders													$ 161,170	$ 153,821	$ 139,012
Weighted average common shares outstanding (in shares)													26,833,079	29,227,071	31,729,596
Effect of dilutive securities
Total effect of dilutive securities (in shares)													92,527	5,176	21,926
Total weighted average diluted common shares outstanding (in shares)													26,925,606	29,232,247	31,751,522
Basic earnings per common share (in dollars per share)	$ 1.37	$ 1.69	$ 1.99	$ 0.98	$ 0.81	$ 0.76	$ 1.66	$ 2.00	$ 0.50	$ 1.21	$ 1.84	$ 0.84	$ 6.01	$ 5.26	$ 4.38
Diluted earnings per common share (in dollars per share)	$ 1.36	$ 1.68	$ 1.99	$ 0.98	$ 0.81	$ 0.76	$ 1.66	$ 2.00	$ 0.50	$ 1.21	$ 1.84	$ 0.84	$ 5.99	$ 5.26	$ 4.38
Weighted average shares of nonvested restricted stock, antidilutive (in shares)													408,477	487,476	615,811
Performance share units
Effect of dilutive securities
Outstanding options - based upon the two-class method (in shares)													92,527	5,176	21,926