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		24,187
Net realized gain (loss) on investments, financial derivatives, and foreign currency transactions		(11,247)
Change in net unrealized gain (loss) on investments, financial derivatives, and foreign currency translation		84,206
Net Income (Loss) Attributable to Parent		97,146		97,146
Net Income (Loss) Attributable to Noncontrolling Interest		0			0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		97,146
CHANGE IN EQUITY RESULTING FROM TRANSACTIONS
Proceeds from the issuance of shares	[1]	88,142		88,142
Shares issued in connection with incentive fee payment		1,180		1,180
Contribution from non-controlling interests		0			0
Dividends	[2]	(47,412)	[3]	(47,412)	0
Distributions to non-controlling interest		0			0
Adjustment to non-controlling interest		0		0	0
Shares repurchased		(3,430)		(3,430)
Offering costs		(322)		(322)
Share-based LTIP awards		135		135	0
Net increase (decrease) in equity from transactions		38,293		38,293	0
Net increase in equity		135,439		135,439	0
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		49,655
Net realized gain (loss) on investments, financial derivatives, and foreign currency transactions		18,002
Change in net unrealized gain (loss) on investments, financial derivatives, and foreign currency translation		11,705
Net Income (Loss) Attributable to Parent		78,524		78,524
Net Income (Loss) Attributable to Noncontrolling Interest		838			838
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		79,362
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		1,262		1,262
Contribution from non-controlling interests		5,880			5,880
Dividends	[2]	(92,067)	[3]	(91,256)	(811)
Distributions to non-controlling interest		(260)			(260)
Adjustment to non-controlling interest		0		0	0
Shares repurchased		0		0
Offering costs		(262)		(262)
Share-based LTIP awards		179		178	1
Net increase (decrease) in equity from transactions		40,332		35,522	4,810
Net increase in equity		119,694		114,046	5,648
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		58,751
Net realized gain (loss) on investments, financial derivatives, and foreign currency transactions		4,162
Change in net unrealized gain (loss) on investments, financial derivatives, and foreign currency translation		(2,964)
Net Income (Loss) Attributable to Parent		59,167		59,167
Net Income (Loss) Attributable to Noncontrolling Interest		782			782
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		59,949
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		449		449
Contribution from non-controlling interests		1,793			1,793
Dividends	[2]	(86,449)	[3]	(85,796)	(653)
Distributions to non-controlling interest		(1,667)			(1,667)
Adjustment to non-controlling interest		0		(484)	484
Shares repurchased		0		0
Offering costs		(247)		(247)
Share-based LTIP awards		267		265	2
Net increase (decrease) in equity from transactions		102,546		102,587	(41)
Net increase in equity		162,495		161,754	741
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2014		788,544
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2014		6,389			6,389
Stockholders' Equity Attributable to Parent at Dec. 31, 2014		$ 782,155		$ 782,155

[1] Proceeds from the issuance of shares is net of an underwriters' discount of $3.0 million and $1.9 million for the years ended December 31, 2014 and 2012, respectively.

[2] For the years ended December 31, 2014, 2013, and 2012, dividends totaling $3.08, $3.83, and $2.50, 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.