FAIR VALUE (Deposits held for sale narrative) (Details)	12 Months Ended
Dec. 31, 2018 USD ($) branch	Sep. 30, 2019 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits held for sale	$ 9,396,429,000	$ 10,469,856,000
Disposal Group, Held-for-sale, Not Discontinued Operations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits held for sale	$ 106,400,000	$ 0
Number of branch locations \| branch	5

The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Name:	us-gaap_Deposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant