Consolidated Balance Sheets (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	$ 72,029,000	$ 92,547,000
Preferred Stock, Liquidation Preference, Value	1,538,000	$ 963,000
Preferred Stock C, Liquidation Preference, Value	325,000
Preferred Stock D, Liquidation Preference, Value	$ 235,000
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	1,500,000	900,000
Common Stock, Shares, Issued	555,500	540,900
Common Stock, Shares, Outstanding		540,900
Agency Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	$ 69,956,000	$ 92,608,000
Credit Risk Transfer Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	490,000	309,000
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	511,000	0
US Treasury Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	1,136,000	481,000
Receivable for securities sold [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	480,000
Asset Pledged as Collateral [Member] | Credit Risk Transfer Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	479,000	309,000
Asset Pledged as Collateral [Member] | US Treasury Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	$ 1,136,000	$ 97,000