DEBT OBLIGATIONS - Narrative (Details) $ in Thousands	Dec. 31, 2019 USD ($) agreement
Debt Instrument [Line Items]
Face Amount of Notes and Bonds Payable	$ 35,650,844
Repurchase Agreements: \| Repurchase Agreements
Debt Instrument [Line Items]
Face Amount of Notes and Bonds Payable	$ 27,917,709
Repurchase Agreements: \| Stockholders' Equity \| Counterpary Concentration Risk Exceeding 10%
Debt Instrument [Line Items]
Number of outstanding repurchase agreements \| agreement	0

Face (par) amount of debt instrument at time of issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

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