DESCRIPTION OF THE BUSINESS AND MERGER TRANSACTION - Reconciliation of Common Shares Related to Merger (Details) - shares	Jan. 04, 2021	Mar. 31, 2021	Dec. 31, 2020
Business Description And Reverse Recapitalization [Abstract]
Shares related to the recapitalization transaction - January 4, 2021	6,076,946
Shares held by legacy BankMobile shareholders - December 31, 2020	6,123,432
Common stock, shares issued		12,200,378	6,123,432
Common stock, shares outstanding		12,200,378	6,123,432