Consolidated Statement Of Changes In Equity - USD ($) $ in Thousands		Total		Parent [Member]	Noncontrolling Interest [Member]
Stockholders' Equity Attributable to Parent at Dec. 31, 2014				$ 782,155
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2014					$ 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		52,720
Net realized gain (loss) on investments, financial derivatives, and foreign currency transactions		19,470
Change in net unrealized gain (loss) on investments, financial derivatives, and foreign currency translation		(35,622)
Net Income (Loss) Attributable to Parent		36,309		36,309
Net Income (Loss) Attributable to Noncontrolling Interest		259			259
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		36,568
CHANGE IN EQUITY RESULTING FROM TRANSACTIONS
Contributions from non-controlling interests		1,430			1,430
Dividends	[1]	(66,462)	[2]	(66,048)	(414)
Distributions to non-controlling interest		(1,410)			(1,410)
Adjustment to non-controlling interest		0		0	0
Shares repurchased		(623)		(623)
Share-based LTIP awards		294		292	2
Net increase (decrease) in equity from transactions		(66,771)		(66,379)	(392)
Net increase (decrease) in equity		(30,203)		(30,070)	(133)
Stockholders' Equity Attributable to Parent at Sep. 30, 2015				752,085
Stockholders' Equity Attributable to Noncontrolling Interest at Sep. 30, 2015					6,256
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2015		758,341
Stockholders' Equity Attributable to Parent at Dec. 31, 2015		732,049		732,049
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2015		6,903			6,903
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2015		738,952
CHANGE IN SHAREHOLDERS’ EQUITY RESULTING FROM OPERATIONS
Net investment income		26,738
Net realized gain (loss) on investments, financial derivatives, and foreign currency transactions		(37,291)
Change in net unrealized gain (loss) on investments, financial derivatives, and foreign currency translation		(7,080)
Net Income (Loss) Attributable to Parent		(17,699)		(17,699)
Net Income (Loss) Attributable to Noncontrolling Interest		66			66
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		(17,633)
CHANGE IN EQUITY RESULTING FROM TRANSACTIONS
Contributions from non-controlling interests		4,747			4,747
Dividends	[1]	(50,256)	[2]	(49,938)	(318)
Distributions to non-controlling interest		(2,560)			(2,560)
Adjustment to non-controlling interest		0		(10)	10
Shares repurchased		(8,797)		(8,797)
Share-based LTIP awards		300		298	2
Net increase (decrease) in equity from transactions		(56,566)		(58,447)	1,881
Net increase (decrease) in equity		(74,199)		(76,146)	1,947
Stockholders' Equity Attributable to Parent at Sep. 30, 2016		655,903		$ 655,903
Stockholders' Equity Attributable to Noncontrolling Interest at Sep. 30, 2016		8,850			$ 8,850
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2016		$ 664,753

[1] For the nine month periods ended September 30, 2016 and 2015, dividends totaling $1.50 and $1.95, 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.