Consolidated Condensed Schedule Of Investments (Investments Sold Short) - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015
Investments Sold, Not yet Purchased [Line Items]
Investments sold short, at fair value-		$ (584,896)		$ (728,747)
Proceeds from investments sold short		$ (589,429)		$ (731,048)
TBA - Fixed Rate Agency Securities Sold Short [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(62.77%)	[1],[2],[3]	(82.93%)	[4],[5],[6]
Current Principal/Notional Amount		$ (384,155)		$ (580,992)
Investments sold short, at fair value-		(404,728)	[1],[3]	(612,777)	[4],[6]
Proceeds from investments sold short		$ (404,967)	[1],[3]	$ (612,749)	[4],[6]
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		(32.67%)		(57.51%)
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		(22.21%)		(23.25%)
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		(7.89%)		(2.17%)
Government debt [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(20.54%)	[2],[3]	(15.43%)	[5],[6]
Investments sold short, at fair value-		$ (132,442)	[3]	$ (114,051)	[6]
Proceeds from investments sold short		$ (136,746)	[3]	$ (115,745)	[6]
Common Stock Sold Short [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(1.26%)	[2],[3]	(0.20%)	[5],[6]
Investments sold short, at fair value-		$ (8,154)	[3]	$ (1,471)	[6]
Proceeds from investments sold short		$ (8,052)	[3]	$ (1,878)	[6]
Corporate Debt Sold Short [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(6.14%)	[2],[3]	(0.06%)	[5],[6]
Investments sold short, at fair value-		$ (39,572)	[3]	$ (448)	[6]
Proceeds from investments sold short		$ (39,664)	[3]	$ (676)	[6]
Investments Sold Short [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(90.71%)	[2],[3]	(98.62%)	[5],[6]
Investments sold short, at fair value-		$ (584,896)	[3]	$ (728,747)	[6]
Proceeds from investments sold short		$ (589,429)	[3]	$ (731,048)	[6]
North America [Member] | US Government Debt Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(10.82%)	[2],[3]	(12.11%)	[5],[6]
Investments sold short, at fair value-		$ (69,762)	[3]	$ (89,489)	[6]
Proceeds from investments sold short		$ (69,946)	[3]	$ (89,735)	[6]
Europe [Member] | Foreign Government Debt Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Investment Sold, Not yet Purchased, Percent of Equity		(9.72%)	[2],[3]	(3.32%)	[5],[6]
Investments sold short, at fair value-		$ (62,680)	[3]	$ (24,562)	[6]
Proceeds from investments sold short		(66,800)	[3]	(26,010)	[6]
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		$ (87,767)	[1],[3]	$ (110,327)	[4],[6]
Rate		4.00%	[1],[3]	4.00%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (92,210)	[1],[3]	$ (116,593)	[4],[6]
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		$ (50,930)	[1],[3]	$ (79,210)	[4],[6]
Rate		4.50%	[1],[3]	4.50%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (54,748)	[1],[3]	$ (85,553)	[4],[6]
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	[4],[6]			$ (69,760)
Rate	[4],[6]			3.50%
Investments maturity date	[4],[6]			2016-01
Investments sold short, at fair value-	[4],[6]			$ (73,054)
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		$ (31,620)	[1],[3]	$ (51,970)	[4],[6]
Rate		5.00%	[1],[3]	5.00%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (34,426)	[1],[3]	$ (57,214)	[4],[6]
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		$ (26,000)	[1],[3]	$ (48,200)	[4],[6]
Rate		4.00%	[1],[3]	4.00%	[4],[6]
Investments maturity date		2017-02	[1],[3]	2016-02	[4],[6]
Investments sold short, at fair value-		$ (27,295)	[1],[3]	$ (50,911)	[4],[6]
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		$ (24,352)	[1],[3]	$ (43,842)	[4],[6]
Rate		3.50%	[1],[3]	3.50%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (24,960)	[1],[3]	$ (45,233)	[4],[6]
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		$ (23,151)	[1],[3]	$ (21,881)	[4],[6]
Rate		4.50%	[1],[3]	4.50%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (24,840)	[1],[3]	$ (23,577)	[4],[6]
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		$ (21,940)	[1],[3]	$ (5,050)	[4],[6]
Rate		3.50%	[1],[3]	3.50%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (22,819)	[1],[3]	$ (5,267)	[4],[6]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal National Mortgage Association (30 Year) 4.00% 2017 01 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[1],[3]	$ (20,558)
Rate	[1],[3]	4.00%
Investments maturity date	[1],[3]	2017-01
Investments sold short, at fair value-	[1],[3]	$ (21,611)
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	[1],[3]	$ (20,740)
Rate	[1],[3]	3.00%
Investments maturity date	[1],[3]	2017-01
Investments sold short, at fair value-	[1],[3]	$ (21,285)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Government National Mortgage Association (30 Year) 4.50% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[1],[3]	$ (15,770)
Rate	[1],[3]	4.50%
Investments maturity date	[1],[3]	2017-01
Investments sold short, at fair value-	[1],[3]	$ (17,058)
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		$ (13,510)	[1],[3]	$ (16,510)	[4],[6]
Rate		3.00%	[1],[3]	3.00%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (13,869)	[1],[3]	$ (17,018)	[4],[6]
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]	$ (11,170)	[4],[6]
Rate		4.00%	[1],[3]	4.00%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (11,494)	[1],[3]	$ (11,629)	[4],[6]
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		$ (8,790)	[1],[3]	$ (13,980)	[4],[6]
Rate		3.50%	[1],[3]	3.50%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (9,169)	[1],[3]	$ (14,618)	[4],[6]
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]
Rate		5.50%	[1],[3]	5.50%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (7,622)	[1],[3]	$ (7,646)	[4],[6]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Government National Mortgage Association (30 Year) 3.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[1],[3]	$ (6,500)
Rate	[1],[3]	3.00%
Investments maturity date	[1],[3]	2017-01
Investments sold short, at fair value-	[1],[3]	$ (6,568)
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		$ (4,612)	[1],[3]	$ (23,600)	[4],[6]
Rate		3.00%	[1],[3]	3.00%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-02	[4],[6]
Investments sold short, at fair value-		$ (4,584)	[1],[3]	$ (23,555)	[4],[6]
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Federal Home Loan Mortgage Corporation (30 Year) 3.00% [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[1],[3]	$ (3,155)
Rate	[1],[3]	3.00%
Investments maturity date	[1],[3]	2017-01
Investments sold short, at fair value-	[1],[3]	$ (3,134)
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	[1],[3]	$ (2,530)
Rate	[1],[3]	3.50%
Investments maturity date	[1],[3]	2017-02
Investments sold short, at fair value-	[1],[3]	$ (2,633)
Mortgage-related Residential [Member] | North America [Member] | TBA - Fixed Rate Agency Securities Sold Short [Member] | Government National Mortgage Association (30 Year) 3.50% 2017 02 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[1],[3]	$ (2,500)
Rate	[1],[3]	3.50%
Investments maturity date	[1],[3]	2017-02
Investments sold short, at fair value-	[1],[3]	$ (2,597)
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		$ (1,700)	[1],[3]	$ (10,150)	[4],[6]
Rate		4.00%	[1],[3]	4.00%	[4],[6]
Investments maturity date		2017-01	[1],[3]	2016-01	[4],[6]
Investments sold short, at fair value-		$ (1,806)	[1],[3]	$ (10,782)	[4],[6]
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	[4],[6]			$ (37,140)
Rate	[4],[6]			3.00%
Investments maturity date	[4],[6]			2016-01
Investments sold short, at fair value-	[4],[6]			$ (38,264)
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	[4],[6]			$ (17,600)
Rate	[4],[6]			3.50%
Investments maturity date	[4],[6]			2016-02
Investments sold short, at fair value-	[4],[6]			$ (18,120)
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	[4],[6]			$ (13,742)
Rate	[4],[6]			3.00%
Investments maturity date	[4],[6]			2016-01
Investments sold short, at fair value-	[4],[6]			$ (13,743)
Government [Member] | North America [Member] | US Government Debt Securities [Member] | U.S. Treasury Note, 2.00 Percent, Maturity Date 2026 11 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (48,133)
Rate	[3]	2.00%
Investments maturity date	[3]	2026-11
Investments sold short, at fair value-	[3]	$ (46,287)
Government [Member] | North America [Member] | US Government Debt Securities [Member] | US Treasury Note, 1.50 Percent, Maturity Date 2026 08 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (12,160)
Rate	[3]	1.50%
Investments maturity date	[3]	2026-08
Investments sold short, at fair value-	[3]	$ (11,179)
Government [Member] | North America [Member] | US Government Debt Securities [Member] | US Treasury Note, 1.75 Percent, Maturity Date 2021 11 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (4,726)
Rate	[3]	1.75%
Investments maturity date	[3]	2021-11
Investments sold short, at fair value-	[3]	$ (4,690)
Government [Member] | North America [Member] | US Government Debt Securities [Member] | US Treasury Note, 1.13 Percent, Maturity Date 2021 08 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (3,230)
Rate	[3]	1.13%
Investments maturity date	[3]	2021-08
Investments sold short, at fair value-	[3]	$ (3,121)
Government [Member] | North America [Member] | US Government Debt Securities [Member] | US Treasury Note, 1.13 Percent, Maturity Date 2021 09 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (1,968)
Rate	[3]	1.13%
Investments maturity date	[3]	2021-09
Investments sold short, at fair value-	[3]	$ (1,898)
Government [Member] | North America [Member] | US Government Debt Securities [Member] | US Treasury Note, 1.38 Percent, Maturity Date 2021 04 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (1,305)
Rate	[3]	1.38%
Investments maturity date	[3]	2021-04
Investments sold short, at fair value-	[3]	$ (1,280)
Government [Member] | North America [Member] | US Government Debt Securities [Member] | US Treasury Note, 1.25 Percent, Maturity Date 2021 10 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (800)
Rate	[3]	1.25%
Investments maturity date	[3]	2021-10
Investments sold short, at fair value-	[3]	$ (776)
Government [Member] | North America [Member] | US Government Debt Securities [Member] | US Treasury Note, 1.13 Percent, Maturity Date 2021 07 [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (549)
Rate	[3]	1.13%
Investments maturity date	[3]	2021-07
Investments sold short, at fair value-	[3]	$ (531)
Government [Member] | North America [Member] | US Government Debt Securities [Member] | US Treasury Notes Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[6]			(90,120)
Investments sold short, at fair value-	[6]			$ (89,489)
Government [Member] | North America [Member] | US Government Debt Securities [Member] | Minimum [Member] | US Treasury Notes Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate	[6]			1.25%
Investments maturity date	[6]			2018-10
Government [Member] | North America [Member] | US Government Debt Securities [Member] | Maximum [Member] | US Treasury Notes Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate	[6]			2.25%
Investments maturity date	[6]			2025-08
Government [Member] | Europe [Member] | Foreign Government Debt Securities [Member] | Sovereign Debt Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (20,754)	[3]	$ (23,907)	[6]
Investments maturity date	[3]	2020-11
Investments sold short, at fair value-		$ (21,219)	[3]	$ (24,562)	[6]
Government [Member] | Europe [Member] | Foreign Government Debt Securities [Member] | Spanish Sovereign Bond, 0.25 Percent [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (14,507)
Rate	[3]	0.25%
Investments maturity date	[3]	2018-04
Investments sold short, at fair value-	[3]	$ (14,614)
Government [Member] | Europe [Member] | Foreign Government Debt Securities [Member] | Spanish Sovereign Bond, 0.75 Percent [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (9,176)
Rate	[3]	0.75%
Investments maturity date	[3]	2021-07
Investments sold short, at fair value-	[3]	$ (9,379)
Government [Member] | Europe [Member] | Foreign Government Debt Securities [Member] | Spanish Sovereign Bond, 2.75 Percent [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (8,322)
Rate	[3]	2.75%
Investments maturity date	[3]	2019-04
Investments sold short, at fair value-	[3]	$ (8,888)
Government [Member] | Europe [Member] | Foreign Government Debt Securities [Member] | Spanish Sovereign Bond, 1.15 Percent [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (8,257)
Rate	[3]	1.15%
Investments maturity date	[3]	2020-07
Investments sold short, at fair value-	[3]	$ (8,580)
Government [Member] | Europe [Member] | Foreign Government Debt Securities [Member] | Minimum [Member] | Sovereign Debt Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate		0.25%	[3]	0.25%	[6]
Investments maturity date	[6]			2016-09
Government [Member] | Europe [Member] | Foreign Government Debt Securities [Member] | Maximum [Member] | Sovereign Debt Securities [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate		0.65%	[3]	4.00%	[6]
Investments maturity date	[6]			2019-04
Basic Materials [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (8,970)
Investments sold short, at fair value-	[3]	$ (8,717)
Basic Materials [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Minimum [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate	[3]	3.88%
Investments maturity date	[3]	2021-10
Basic Materials [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Maximum [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate	[3]	5.13%
Investments maturity date	[3]	2023-03
Communications [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (8,750)
Investments sold short, at fair value-	[3]	$ (8,551)
Communications [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Minimum [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate	[3]	5.25%
Investments maturity date	[3]	2021-07
Communications [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Maximum [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate	[3]	9.25%
Investments maturity date	[3]	2022-09
Consumer [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (8,930)
Investments sold short, at fair value-	[3]	$ (8,695)
Consumer [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Minimum [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate	[3]	3.88%
Investments maturity date	[3]	2022-01
Consumer [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Maximum [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate	[3]	6.25%
Investments maturity date	[3]	2026-04
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-	[6]			$ (1,471)
Investment Sold, Not yet Purchased, Balance, Shares	[6]			(306)
Energy [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount		$ (10,597)	[3]	$ (1,120)	[6]
Investments sold short, at fair value-		$ (10,041)	[3]	$ (448)	[6]
Energy [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Minimum [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate		2.40%	[3]	10.00%	[6]
Investments maturity date		2021-06	[3]	2020-03	[6]
Energy [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Maximum [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Rate		8.00%	[3]	11.00%	[6]
Investments maturity date		2025-01	[3]	2020-06	[6]
Financial [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]	$ (8,154)
Investment Sold, Not yet Purchased, Balance, Shares	[3]	(207)
Financial [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (1,130)
Rate	[3]	4.13%
Investments maturity date	[3]	2022-02
Investments sold short, at fair value-	[3]	$ (1,121)
Utilities [Member] | North America [Member] | Corporate Debt Sold Short [Member] | Various Issuer [Member]
Investments Sold, Not yet Purchased [Line Items]
Current Principal/Notional Amount	[3]	$ (2,430)
Rate	[3]	6.25%
Investments maturity date	[3]	2022-07
Investments sold short, at fair value-	[3]	$ (2,447)

[1] At December 31, 2016, 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 32.67%, 22.21%, and 7.89% 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, 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.

[5] Classification percentages are based on Total Equity.

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