COMMITMENTS AND CONTINGENCIES (Details)		3 Months Ended
	Feb. 09, 2018 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2019 USD ($) commitment	Dec. 24, 2018 USD ($)	Sep. 30, 2018 USD ($) commitment	Oct. 14, 2016 USD ($)
Loss Contingencies [Line Items]
Unfunded loan commitments			$ 860,400,000		$ 748,800,000
Number of investment commitments | commitment			0		1,400,000
Securities, buy (sell) obligations			$ 0		$ 0
Concentration Risk, Credit Risk, Financial Instrument, Off-Balance Sheet Valuation Allowance			$ 100,000		$ 100,000
Inter National Bank [Member]
Loss Contingencies [Line Items]
Amount of shortfall in depository account		$ 10,500,000
Card Limited, LLC v. MetaBank dba Meta Payment Systems [Member]
Loss Contingencies [Line Items]
Estimate of possible loss						$ 4,000,000
AFS/IBEX, A Division of MetaBank V. Aegis Managing Agency Limited [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Sought, Value	$ 1,600,000
Ohio Valley Bank Company V. Metabank dba Refund Advantage, Case No. 18 CV 134 [Member]
Loss Contingencies [Line Items]
Estimate of possible loss				$ 3,000,000