Consolidated Statement Of Changes In Equity - USD ($) $ in Thousands		Total		Parent [Member]	Noncontrolling Interest [Member]
Stockholders' Equity Attributable to Parent at Dec. 31, 2013				$ 620,401
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2013					$ 5,648
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2013		$ 626,049
CHANGE IN SHAREHOLDERS’ EQUITY RESULTING FROM OPERATIONS
Net investment income	[1]	27,087
Net realized gain (loss) on investments, financial derivatives, and foreign currency transactions	[1]	15,093
Change in net unrealized gain (loss) on investments, financial derivatives, and foreign currency translation	[1]	1,862
Net Income (Loss) Attributable to Parent		43,582	[1]	43,582
Net Income (Loss) Attributable to Noncontrolling Interest		460	[1]		460
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	[1]	44,042
CHANGE IN EQUITY RESULTING FROM TRANSACTIONS
Shares issued in connection with incentive fee payment		309		309
Contributions from non-controlling interests		1,201			1,201
Dividends	[2]	(40,140)	[3]	(39,814)	(326)
Distributions to non-controlling interest		(465)			(465)
Adjustment to non-controlling interest		0		(497)	497
Share-based LTIP awards		127		126	1
Net increase (decrease) in equity from transactions		(38,968)		(39,876)	908
Net increase (decrease) in equity		5,074		3,706	1,368
Stockholders' Equity Attributable to Parent at Jun. 30, 2014				624,107
Stockholders' Equity Attributable to Noncontrolling Interest at Jun. 30, 2014					7,016
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2014		631,123
Stockholders' Equity Attributable to Parent at Dec. 31, 2014		782,155		782,155
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2014		6,389			6,389
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2014		788,544
CHANGE IN SHAREHOLDERS’ EQUITY RESULTING FROM OPERATIONS
Net investment income		35,197
Net realized gain (loss) on investments, financial derivatives, and foreign currency transactions		11,190
Change in net unrealized gain (loss) on investments, financial derivatives, and foreign currency translation		(13,747)
Net Income (Loss) Attributable to Parent		32,413		32,413
Net Income (Loss) Attributable to Noncontrolling Interest		227			227
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		32,640
CHANGE IN EQUITY RESULTING FROM TRANSACTIONS
Shares issued in connection with incentive fee payment		0		0
Contributions from non-controlling interests		1,430			1,430
Dividends	[2]	(44,318)	[3]	(44,044)	(274)
Distributions to non-controlling interest		(1,410)			(1,410)
Adjustment to non-controlling interest		0		0	0
Share-based LTIP awards		196		195	1
Net increase (decrease) in equity from transactions		(44,102)		(43,849)	(253)
Net increase (decrease) in equity		(11,462)		(11,436)	(26)
Stockholders' Equity Attributable to Parent at Jun. 30, 2015		770,719		$ 770,719
Stockholders' Equity Attributable to Noncontrolling Interest at Jun. 30, 2015		6,363			$ 6,363
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2015		$ 777,082

[1] Conformed to current period presentation.

[2] For the six month periods ended June 30, 2015 and 2014, dividends totaling $1.30 and $1.54, 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.