Consolidated Statement Of Assets, Liabilities And Equity (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Investments at value, cost	$ 2,391,276	$ 1,688,257
Financial derivatives–assets, at fair value Net cost	45,074	50,533
Repurchase agreements, cost	47,192	27,943
Investments sold short at value, proceeds	(1,223,043)	(847,602)
Financial derivatives-liabilities, at fair value Net proceeds	(33,950)	(29,746)
Securitized debt proceeds	$ (849)	$ (980)
Common stock, par value
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	33,443,572	25,428,186
Common stock, shares outstanding	33,443,572	25,428,186