SEGMENT REPORTING (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Sep. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	3
Segment data [Abstract]
Net interest income	$ 60,272	$ 26,196
Provision for loan and lease losses	9,099	1,068
Noninterest income	37,751	29,268
Noninterest expense	74,295	44,042
Income (loss) before income tax expense (benefit)	14,629	10,354
Total assets	6,182,765	5,417,963	$ 5,835,067
Total goodwill	303,270	98,723	303,270
Total deposits	4,936,447	3,513,645	$ 4,430,987
Meta Payment Systems [Member]
Segment data [Abstract]
Net interest income	9,400	4,669
Provision for loan and lease losses	1,495	1,017
Noninterest income	22,826	28,101
Noninterest expense	21,362	26,934
Income (loss) before income tax expense (benefit)	9,369	4,819
Total assets	302,368	380,442
Total goodwill	87,145	87,145
Total deposits	2,753,702	2,768,736
Banking [Member]
Segment data [Abstract]
Net interest income	51,792	15,597
Provision for loan and lease losses	7,604	51
Noninterest income	14,269	1,485
Noninterest expense	33,843	6,568
Income (loss) before income tax expense (benefit)	24,614	10,463
Total assets	3,793,647	1,478,693
Total goodwill	216,125	11,578
Total deposits	554,939	236,494
Corporate Services/Other [Member]
Segment data [Abstract]
Net interest income	(920)	5,930
Provision for loan and lease losses	0	0
Noninterest income	656	(318)
Noninterest expense	19,090	10,540
Income (loss) before income tax expense (benefit)	(19,354)	(4,928)
Total assets	2,086,750	3,558,828
Total goodwill	0	0
Total deposits	$ 1,627,806	$ 508,415