Consolidated Statement Of Changes In Shareholders' Equity (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
CHANGE IN SHAREHOLDERS' EQUITY RESULTING FROM OPERATIONS
Net investment income	$ 10,960		$ 10,598
Net realized gain (loss) on investments and financial derivatives	(11,789)		11,604
Change in net unrealized gain (loss) on investments and financial derivatives	32,884		(11,095)
Net increase in shareholders' equity resulting from operations	32,055		11,107
CHANGE IN SHAREHOLDERS' EQUITY RESULTING FROM SHAREHOLDER TRANSACTIONS
Shares issued in connection with incentive fee payment			142
Dividends paid	(6,735)	[1]	(22,126)	[1]
Share-based LTIP awards	28		38
Net decrease in shareholders' equity from shareholder transactions	(6,707)		(21,946)
Net increase (decrease) in shareholders' equity	25,348		(10,839)
SHAREHOLDERS' EQUITY, BEGINNING OF PERIOD	370,916		403,672
SHAREHOLDERS' EQUITY, END OF PERIOD	$ 396,264		$ 392,833

[1] For the three month periods ending March 31, 2012 and 2011, dividends totaling $0.40 and $1.31, respectively, per common share and LTIP unit outstanding were declared and paid.