Consolidated Statement Of Changes In Shareholders' Equity (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
CHANGE IN SHAREHOLDERS' EQUITY RESULTING FROM OPERATIONS
Net investment income	$ 732		$ 10,977		$ 20,514		$ 33,649
Net realized gain (loss) on investments and financial derivatives	4,943		7,974		(18,126)		15,662
Change in net unrealized gain (loss) on investments and financial derivatives	23,862		(20,111)		69,972		(40,685)
Net increase (decrease) in shareholders' equity resulting from operations	29,537		(1,160)		72,360		8,626
CHANGE IN SHAREHOLDERS' EQUITY RESULTING FROM SHAREHOLDER TRANSACTIONS
Net proceeds from the issuance of shares	88,142	[1]	0	[1]	88,142	[1]	0	[1]
Shares issued in connection with incentive fee payment	231		0		231		203
Dividends paid	(14,244)	[2]	(6,752)	[2]	(32,766)	[2]	(35,634)	[2]
Shares repurchased	0		(309)		0		(309)
Net offering costs	(322)		0		(322)		0
Share-based LTIP awards	31		41		89		116
Net increase (decrease) in shareholders' equity from shareholder transactions	73,838		(7,020)		55,374		(35,624)
Net increase (decrease) in shareholders' equity	103,375		(8,180)		127,734		(26,998)
SHAREHOLDERS' EQUITY, BEGINNING OF PERIOD	395,275		384,854		370,916		403,672
SHAREHOLDERS' EQUITY, END OF PERIOD	$ 498,650		$ 376,674		$ 498,650		$ 376,674

[1] Proceeds from the issuance of shares are net of placement fees in the amount of $1,852.

[2] For the three month periods ending September 30, 2012 and 2011, dividends totaling $0.70 and $0.40, respectively, per common share and LTIP unit outstanding were declared and paid. For the nine month periods ending September 30, 2012 and 2011, dividends totaling $1.80 and $2.11, respectively, per common share and LTIP unit outstanding were declared and paid.