Condensed Consolidated Balance Sheet (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Investments at value, cost		$ 2,970,306,000
Financial derivatives–assets, net cost		22,526,000
Repurchase agreements, cost		61,274,000
Investments sold short at value, proceeds		(844,604,000)
Financial derivatives-liabilities, at fair value Net proceeds		(19,019,000)
Other secured borrowings proceeds		(114,100,000)
Other secured financing, at fair value-Proceeds		$ (298,706,000)
Common shares	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	38,647,943	29,796,601
Common stock, shares outstanding	38,647,943	29,796,601
Preferred Stock, Par or Stated Value Per Share	$ 0.001
Preferred Stock, Shares Authorized	100,000,000
Preferred Stock, Shares Issued	4,600,000
Preferred Stock, Shares Outstanding	4,600,000
Preferred Stock, Dividend Rate, Percentage	6.75%
Preferred Stock, Liquidation Preference, Value	$ 115,000