Consolidated Condensed Schedule Of Investments (Investments Sold Short) - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014
Investments Sold, Not yet Purchased [Line Items]
Investments sold short, at fair value-		$ (728,747)		$ (1,291,370)
Proceeds from investments sold short		$ (731,048)		$ (1,290,091)
TBA - Fixed Rate Agency Securities Sold Short [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(82.93%)	[1],[2],[3]	(153.39%)	[4],[5],[6],[7]
Current Principal/Notional Amount		$ (580,992)		$ (1,135,218)
Investments sold short, at fair value-		(612,777)	[1],[3]	(1,209,539)	[4],[6],[7]
Proceeds from investments sold short		$ (612,749)	[1],[3]	$ (1,205,876)	[4],[6],[7]
TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(57.51%)		(121.95%)
TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(23.25%)		(31.44%)
TBA - Fixed Rate Agency Securities Sold Short [Member] | Government National Mortgage Association [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(2.17%)
Government debt sold short [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(15.43%)	[2],[3]	(7.02%)	[5],[6],[7]
Investments sold short, at fair value-		$ (114,051)	[3]	$ (55,315)	[6],[7]
Proceeds from investments sold short		$ (115,745)	[3]	$ (56,610)	[6],[7]
Corporate Debt Sold Short [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity	[2],[3]	(0.06%)
Investments sold short, at fair value-	[3]	$ (448)
Proceeds from investments sold short	[3]	$ (676)
Common Stock Sold Short [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(0.20%)	[2],[3]	(3.36%)	[5],[6],[7]
Investments sold short, at fair value-		$ (1,471)	[3]	$ (26,516)	[6],[7]
Proceeds from investments sold short		$ (1,878)	[3]	$ (27,605)	[6],[7]
Securities Sold Short - Securities Sold, Not Yet Purchased [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(98.62%)	[2],[3]	(163.77%)	[5],[6],[7]
Investments sold short, at fair value-		$ (728,747)	[3]	$ (1,291,370)	[6],[7]
Proceeds from investments sold short		$ (731,048)	[3]	$ (1,290,091)	[6],[7]
North America [Member] | Government debt sold short [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(12.11%)	[2],[3]	(3.14%)	[5],[6],[7]
Investments sold short, at fair value-		$ (89,489)	[3]	$ (24,709)	[6],[7]
Proceeds from investments sold short		$ (89,735)	[3]	$ (24,602)	[6],[7]
Europe [Member] | Government debt sold short [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(3.32%)	[2],[3]	(3.88%)	[5],[6],[7]
Investments sold short, at fair value-		$ (24,562)	[3]	$ (30,606)	[6],[7]
Proceeds from investments sold short		(26,010)	[3]	(32,008)	[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation (30 Year) 4.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (110,327)	[1],[3]	$ (123,117)	[4],[6],[7]
Rate		4.00%	[1],[3]	4.00%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-01	[4],[6],[7]
Investments sold short, at fair value-		$ (116,593)	[1],[3]	$ (131,254)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 4.50% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (79,210)	[1],[3]	$ (48,800)	[4],[6],[7]
Rate		4.50%	[1],[3]	4.50%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-02	[4],[6],[7]
Investments sold short, at fair value-		$ (85,553)	[1],[3]	$ (52,889)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (15 year) 3.50% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (69,760)	[1],[3]	$ (146,580)	[4],[6],[7]
Rate		3.50%	[1],[3]	3.50%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-01	[4],[6],[7]
Investments sold short, at fair value-		$ (73,054)	[1],[3]	$ (154,837)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 5.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (51,970)	[1],[3]	$ (54,100)	[4],[6],[7]
Rate		5.00%	[1],[3]	5.00%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-02	[4],[6],[7]
Investments sold short, at fair value-		$ (57,214)	[1],[3]	$ (59,698)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 4.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (48,200)	[1],[3]	$ (213,928)	[4],[6],[7]
Rate		4.00%	[1],[3]	4.00%	[4],[6],[7]
Investments maturity date		2016-02	[1],[3]	2015-01	[4],[6],[7]
Investments sold short, at fair value-		$ (50,911)	[1],[3]	$ (228,376)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 3.50% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (43,842)	[1],[3]	$ (205,082)	[4],[6],[7]
Rate		3.50%	[1],[3]	3.50%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-01	[4],[6],[7]
Investments sold short, at fair value-		$ (45,233)	[1],[3]	$ (213,870)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (15 Year) 3.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (37,140)	[1],[3]	$ (38,360)	[4],[6],[7]
Rate		3.00%	[1],[3]	3.00%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-01	[4],[6],[7]
Investments sold short, at fair value-		$ (38,264)	[1],[3]	$ (39,870)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation (30 Year) 4.50% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (21,881)	[1],[3]	$ (36,081)	[4],[6],[7]
Rate		4.50%	[1],[3]	4.50%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-01	[4],[6],[7]
Investments sold short, at fair value-		$ (23,577)	[1],[3]	$ (39,111)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 3.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[1],[3]	$ (23,600)
Rate	[1],[3]	3.00%
Investments maturity date	[1],[3]	2016-02
Investments sold short, at fair value-	[1],[3]	$ (23,555)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 3.50% 201602 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[1],[3]	$ (17,600)
Rate	[1],[3]	3.50%
Investments maturity date	[1],[3]	2016-02
Investments sold short, at fair value-	[1],[3]	$ (18,120)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation (15 Year) 3.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (16,510)	[1],[3]	$ (4,100)	[4],[6],[7]
Rate		3.00%	[1],[3]	3.00%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-01	[4],[6],[7]
Investments sold short, at fair value-		$ (17,018)	[1],[3]	$ (4,256)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation (15 Year) 3.50% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (13,980)	[1],[3]	$ (20,300)	[4],[6],[7]
Rate		3.50%	[1],[3]	3.50%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-01	[4],[6],[7]
Investments sold short, at fair value-		$ (14,618)	[1],[3]	$ (21,429)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 3.00% 2016-01 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[1],[3]	$ (13,742)
Rate	[1],[3]	3.00%
Investments maturity date	[1],[3]	2016-01
Investments sold short, at fair value-	[1],[3]	$ (13,743)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (15 Year) 4.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (11,170)	[1],[3]	$ (7,900)	[4],[6],[7]
Rate		4.00%	[1],[3]	4.00%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-02	[4],[6],[7]
Investments sold short, at fair value-		$ (11,629)	[1],[3]	$ (8,365)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Government National Mortgage Association (30 year) 4.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[1],[3]	$ (10,150)
Rate	[1],[3]	4.00%
Investments maturity date	[1],[3]	2016-01
Investments sold short, at fair value-	[1],[3]	$ (10,782)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 5.50% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (6,860)	[1],[3]	$ (6,860)	[4],[6],[7]
Rate		5.50%	[1],[3]	5.50%	[4],[6],[7]
Investments maturity date		2016-01	[1],[3]	2015-01	[4],[6],[7]
Investments sold short, at fair value-		$ (7,646)	[1],[3]	$ (7,673)	[4],[6],[7]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Government National Mortgage Association (30 Year) 3.50% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[1],[3]	$ (5,050)
Rate	[1],[3]	3.50%
Investments maturity date	[1],[3]	2016-01
Investments sold short, at fair value-	[1],[3]	$ (5,267)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 4.50% 2015-01 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[4],[6],[7]			$ (92,080)
Rate	[4],[6],[7]			4.50%
Investments maturity date	[4],[6],[7]			2015-01
Investments sold short, at fair value-	[4],[6],[7]			$ (99,968)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 5.00% 2015-01 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[4],[6],[7]			$ (48,150)
Rate	[4],[6],[7]			5.00%
Investments maturity date	[4],[6],[7]			2015-01
Investments sold short, at fair value-	[4],[6],[7]			$ (53,193)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation (30 Year) 4.00% 2015-02 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[4],[6],[7]			$ (26,400)
Rate	[4],[6],[7]			4.00%
Investments maturity date	[4],[6],[7]			2015-02
Investments sold short, at fair value-	[4],[6],[7]			$ (28,071)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 4.00% 201502 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[4],[6],[7]			$ (21,840)
Rate	[4],[6],[7]			4.00%
Investments maturity date	[4],[6],[7]			2015-02
Investments sold short, at fair value-	[4],[6],[7]			$ (23,255)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (15 Year) 2.50% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[4],[6],[7]			$ (15,850)
Rate	[4],[6],[7]			2.50%
Investments maturity date	[4],[6],[7]			2015-01
Investments sold short, at fair value-	[4],[6],[7]			$ (16,140)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation (30 Year) 3.50% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[4],[6],[7]			$ (14,020)
Rate	[4],[6],[7]			3.50%
Investments maturity date	[4],[6],[7]			2015-01
Investments sold short, at fair value-	[4],[6],[7]			$ (14,579)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation (30 year) 5.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[4],[6],[7]			$ (6,000)
Rate	[4],[6],[7]			5.00%
Investments maturity date	[4],[6],[7]			2015-01
Investments sold short, at fair value-	[4],[6],[7]			$ (6,622)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (15 Year) 4.00% 2015-01 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[4],[6],[7]			$ (3,270)
Rate	[4],[6],[7]			4.00%
Investments maturity date	[4],[6],[7]			2015-01
Investments sold short, at fair value-	[4],[6],[7]			$ (3,465)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation (30 Year) 5.50% 2015-01 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[4],[6],[7]			$ (1,300)
Rate	[4],[6],[7]			5.50%
Investments maturity date	[4],[6],[7]			2015-01
Investments sold short, at fair value-	[4],[6],[7]			$ (1,453)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation (15 Year) 4.00% 2015-01 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[4],[6],[7]			$ (1,100)
Rate	[4],[6],[7]			4.00%
Investments maturity date	[4],[6],[7]			2015-01
Investments sold short, at fair value-	[4],[6],[7]			$ (1,165)
Government [Member] | North America [Member] | Government debt sold short [Member] | US Treasury Notes Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		(90,120)	[3]	(22,485)	[6],[7]
Investments sold short, at fair value-		$ (89,489)	[3]	(22,560)	[6],[7]
Government [Member] | North America [Member] | Government debt sold short [Member] | US Treasury Bond Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[6],[7]			$ (2,000)
Rate	[6],[7]			3.13%
Investments maturity date	[6],[7]			2044-08
Investments sold short, at fair value-	[6],[7]			$ (2,149)
Government [Member] | North America [Member] | Government debt sold short [Member] | Minimum [Member] | US Treasury Notes Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate		1.25%	[3]	1.25%	[6],[7]
Investments maturity date		2018-10	[3]	2018-10	[6],[7]
Government [Member] | North America [Member] | Government debt sold short [Member] | Maximum [Member] | US Treasury Notes Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate		2.25%	[3]	2.25%	[6],[7]
Investments maturity date		2025-08	[3]	2024-11	[6],[7]
Government [Member] | Europe [Member] | Government debt sold short [Member] | Sovereign Debt Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (23,907)	[3]	$ (28,118)	[6],[7]
Investments sold short, at fair value-		$ (24,562)	[3]	$ (30,606)	[6],[7]
Government [Member] | Europe [Member] | Government debt sold short [Member] | Minimum [Member] | Sovereign Debt Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate		0.25%	[3]	2.75%	[6],[7]
Investments maturity date		2016-09	[3]	2016-09	[6],[7]
Government [Member] | Europe [Member] | Government debt sold short [Member] | Maximum [Member] | Sovereign Debt Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate		4.00%	[3]	4.00%	[6],[7]
Investments maturity date		2019-04	[3]	2019-04	[6],[7]
Energy [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (1,120)
Investments sold short, at fair value-	[3]	$ (448)
Energy [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Minimum [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate	[3]	10.00%
Investments maturity date	[3]	2020-03
Energy [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Maximum [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate	[3]	11.00%
Investments maturity date	[3]	2020-06
Energy [Member] | North America [Member] | Common Stock Sold Short [Member] | Exchange Traded Equity [Member]
Investments Sold, Not yet Purchased [Line Items]
Investments sold short, at fair value-	[3]	$ (1,471)
Investment Sold, Not yet Purchased, Balance, Shares	[3]	(306)
Financial [Member] | North America [Member] | Common Stock Sold Short [Member] | Publicly Traded Real Estate Investment Trusts [Member]
Investments Sold, Not yet Purchased [Line Items]
Investments sold short, at fair value-	[6],[7]			$ (26,516)
Investment Sold, Not yet Purchased, Balance, Shares	[6],[7]			(2,986)

[1] At December 31, 2015, the Company's short investments guaranteed by the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation, and the Government National Mortgage Association, represented 57.51%, 23.25%, and 2.17% of equity, respectively.

[2] Classification percentages are based on Total Equity.

[3] See Note 2 and Note 3 in Notes to Consolidated Financial Statements.

[4] At December 31, 2014, the Company's short investments guaranteed by the Federal National Mortgage Association and the Federal Home Loan Mortgage Corporation, represented 121.95% and 31.44% of equity, respectively.

[5] Classification percentages are based on Total Equity.

[6] Conformed to current period presentation.

[7] See Note 2 and Note 3 in Notes to Consolidated Financial Statements.