Consolidated Statement Of Changes In Equity (USD $) In Thousands, unless otherwise specified		Total		Parent [Member]	Noncontrolling Interest [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2011		$ 370,916
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2011					0
Stockholders' Equity Attributable to Parent at Dec. 31, 2011				370,916
CHANGE IN SHAREHOLDERS’ EQUITY RESULTING FROM OPERATIONS
Net investment income		10,960
Net realized gain (loss) on investments and financial derivatives		(11,789)
Change in net unrealized gain (loss) on investments and financial derivatives		32,884
Net Income (Loss) Attributable to Parent		32,055		32,055
Net Income (Loss) Attributable to Noncontrolling Interest		0			0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		32,055
CHANGE IN EQUITY RESULTING FROM TRANSACTIONS
Shares issued in connection with incentive fee payment		0		0	0
Noncontrolling Interest, Increase from Equity Issuance or Sale of Parent Equity Interest		0		0	0
Dividends(1)	[1]	(6,735)	[2]	(6,735)	0
Share-based LTIP awards		28		28	0
Net increase (decrease) in equity from transactions		(6,707)		(6,707)	0
Net increase in equity		25,348		25,348	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Mar. 31, 2012		396,264
Stockholders' Equity Attributable to Noncontrolling Interest at Mar. 31, 2012					0
Stockholders' Equity Attributable to Parent at Mar. 31, 2012				396,264
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2012		506,355
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2012		0			0
Stockholders' Equity Attributable to Parent at Dec. 31, 2012		506,355		506,355
CHANGE IN SHAREHOLDERS’ EQUITY RESULTING FROM OPERATIONS
Net investment income		10,569
Net realized gain (loss) on investments and financial derivatives		12,592
Change in net unrealized gain (loss) on investments and financial derivatives		17,585
Net Income (Loss) Attributable to Parent		40,335		40,335
Net Income (Loss) Attributable to Noncontrolling Interest		411			411
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		40,746
CHANGE IN EQUITY RESULTING FROM TRANSACTIONS
Shares issued in connection with incentive fee payment		734		734	0
Noncontrolling Interest, Increase from Equity Issuance or Sale of Parent Equity Interest		4,664		0	4,664
Dividends(1)	[1]	(31,939)	[2]	(31,617)	(322)
Share-based LTIP awards		42		41	1
Net increase (decrease) in equity from transactions		(26,499)		(30,842)	4,343
Net increase in equity		14,247		9,493	4,754
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Mar. 31, 2013		520,602
Stockholders' Equity Attributable to Noncontrolling Interest at Mar. 31, 2013		4,754			4,754
Stockholders' Equity Attributable to Parent at Mar. 31, 2013		$ 515,848		$ 515,848

[1] For the three month period ended March 31, 2013 and 2012, dividends totaling $1.52 and $0.40, respectively, per common share and convertible unit outstanding were declared and paid.

[2] The Company pays quarterly dividends in arrears, so a portion of the dividends paid in each calendar year relate to the prior year's earnings.