RESTRICTED STOCK - Summary of restricted stock (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Restricted stock	$ 37,732	$ 60,707
FHLBNY
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Restricted stock	12,819	$ 60,707
FRB capital stock
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Restricted stock	24,748
Bankers' Bank capital stock (ACBB)
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Restricted stock	$ 165

Investments which are not defined as or included in marketable (debt, equity, or other) securities whose use is restricted in whole or in part, generally by contractual agreements or regulatory requirements. For use in an unclassified balance sheet.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 210
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=120413173&loc=SL6242262-115580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 210
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120413209&loc=SL6242269-115581

Name:	us-gaap_RestrictedInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant