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, 2012		$ 506,355
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2012					0
Stockholders' Equity Attributable to Parent at Dec. 31, 2012				506,355
CHANGE IN SHAREHOLDERS’ EQUITY RESULTING FROM OPERATIONS
Net investment income		37,144
Net realized gain (loss) on investments, financial derivatives, and foreign currency transactions		22,552
Total Net Unrealized Gain Loss On Investments, Financial derivatives, and Foreign currency translation		4,578
Net Income (Loss) Attributable to Parent		63,662		63,662
Net Income (Loss) Attributable to Noncontrolling Interest		612			612
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		64,274
CHANGE IN EQUITY RESULTING FROM TRANSACTIONS
Proceeds from the issuance of shares	[1]	125,600		125,600
Shares issued in connection with incentive fee payment		1,058		1,058
Noncontrolling Interest, Increase from Sale of Parent Equity Interest		4,664			4,664
Dividends	[2]	(72,016)	[3]	(71,368)	(648)
Distributions to non-controlling interest		0			0
Adjustments to non-controlling interests		0		0	0
Offering costs		(262)		(262)
Share-based LTIP awards		129		128	1
Net increase (decrease) in equity from transactions		59,173		55,156	4,017
Net increase in equity		123,447		118,818	4,629
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2013		629,802
Stockholders' Equity Attributable to Noncontrolling Interest at Sep. 30, 2013					4,629
Stockholders' Equity Attributable to Parent at Sep. 30, 2013				625,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2013		626,049
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2013		5,648			5,648
Stockholders' Equity Attributable to Parent at Dec. 31, 2013		620,401		620,401
CHANGE IN SHAREHOLDERS’ EQUITY RESULTING FROM OPERATIONS
Net investment income		39,687
Net realized gain (loss) on investments, financial derivatives, and foreign currency transactions		6,610
Total Net Unrealized Gain Loss On Investments, Financial derivatives, and Foreign currency translation		10,893
Net Income (Loss) Attributable to Parent		56,530		56,530
Net Income (Loss) Attributable to Noncontrolling Interest		660			660
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		57,190
CHANGE IN EQUITY RESULTING FROM TRANSACTIONS
Proceeds from the issuance of shares	[1]	188,400		188,400
Shares issued in connection with incentive fee payment		309		309
Noncontrolling Interest, Increase from Sale of Parent Equity Interest		1,524			1,524
Dividends	[2]	(60,210)	[3]	(59,720)	(490)
Distributions to non-controlling interest		(1,099)			(1,099)
Adjustments to non-controlling interests		0		(486)	486
Offering costs		(247)		(247)
Share-based LTIP awards		191		190	1
Net increase (decrease) in equity from transactions		128,868		128,446	422
Net increase in equity		186,058		184,976	1,082
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2014		812,107
Stockholders' Equity Attributable to Noncontrolling Interest at Sep. 30, 2014		6,730			6,730
Stockholders' Equity Attributable to Parent at Sep. 30, 2014		$ 805,377		$ 805,377

[1] For the nine month period ended September 30, 2014 proceeds from the issuance of shares is net of an underwriters' discount of $3.0 million.

[2] For the nine month periods ended September 30, 2014 and 2013, dividends totaling $2.31 and $3.06, respectively, per common share and convertible unit outstanding, were declared and paid.

[3] 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.