Other Assets (Capital Contributions Made to Loan Origination Partners) (Details) - Loan Originators	3 Months Ended	9 Months Ended
Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)
Other Assets [Line Items]
Equity method investments	$ 31,000,000.0	$ 31,000,000.0
Equity investment, convertible notes	75,000,000.0	75,000,000.0
Impairment on investment	0	65,200,000
Company’s residential whole loans at carrying value are serviced by entities the Company has an investment in	840,500,000	840,500,000
Preferred Stock
Other Assets [Line Items]
Equity method investments	$ 68,000,000.0	$ 68,000,000.0

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
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-URI http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 25
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8813-108599

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant