Consolidated Condensed Schedule Of Investments (Financial Derivatives) (USD $)	12 Months Ended
	Dec. 31, 2012 contracts		Dec. 31, 2011 contracts
Investment Holdings, Other than Securities [Line Items]
Derivative Assets	$ 48,504,000		$ 102,871,000
Fair Value	(15,212,000)		(27,040,000)
Financial derivatives - assets, cost	65,860,000		118,281,000
Derivatives, proceeds	(13,171,000)		(9,636,000)
Deutsche Bank Affiliates Dealer [Member]
Investment Holdings, Other than Securities [Line Items]
Swap assets held by dealer as a percentage of stockholders equity			5.65%
Morgan Stanley Affiliates Dealer [Member]
Investment Holdings, Other than Securities [Line Items]
Swap assets held by dealer as a percentage of stockholders equity			8.15%
Credit Suisse Affiliates Dealer [Member]
Investment Holdings, Other than Securities [Line Items]
Swap assets held by dealer as a percentage of stockholders equity			7.27%
Futures [Member]
Investment Holdings, Other than Securities [Line Items]
Future contract notional	1,000,000		1,000,000
Future contract	1		1
Financial Derivatives - Assets [Member]
Investment Holdings, Other than Securities [Line Items]
Derivative Assets	48,504,000	[1]	102,871,000	[1]
Investment owned as a percentage of net assets	9.58%	[1]	27.73%	[1]
Financial derivatives - assets, cost	65,860,000	[1]	118,281,000	[1]
Financial Derivatives - Assets [Member] | Long Credit Default Swap On Asset Backed Indices [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Credit	[1],[2]
Notional value	10,166,000	[1],[2]
Derivative Assets	765,000	[1],[2]
Financial derivatives - assets, cost	135,000	[1],[2]
Financial Derivatives - Assets [Member] | Long Credit Default Swap On Asset Backed Indices [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2036-06	[1],[2]
Financial Derivatives - Assets [Member] | Long Credit Default Swap On Asset Backed Indices [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2037-12	[1],[2]
Financial Derivatives - Assets [Member] | Long Interest Rate Swaps [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure			Interest Rates	[1],[3],[4]
Notional value			4,500,000	[1],[3],[4]
Range of expiration dates			2016-10	[1],[3],[4]
Derivative Assets			68,000	[1],[3],[4]
Financial Derivatives - Assets [Member] | Short Credit Default Swap On Asset Backed Securities [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Credit	[1],[5]	Credit	[1],[3],[5]
Notional value	(42,121,000)	[1],[5]	(74,787,000)	[1],[3],[5]
Derivative Assets	36,031,000	[1],[5]	61,498,000	[1],[3],[5]
Financial Derivatives - Assets [Member] | Short Credit Default Swap On Asset Backed Securities [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2034-09	[1],[5]	2034-09	[1],[3],[5]
Financial Derivatives - Assets [Member] | Short Credit Default Swap On Asset Backed Securities [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2036-05	[1],[5]	2036-12	[1],[3],[5]
Financial Derivatives - Assets [Member] | Short Credit Default Swap On Asset Backed Indices [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Credit	[1],[6]
Notional value	(66,829,000)	[1],[6]
Derivative Assets	11,703,000	[1],[6]
Financial Derivatives - Assets [Member] | Short Credit Default Swap On Asset Backed Indices [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2046-05	[1],[6]
Financial Derivatives - Assets [Member] | Short Credit Default Swap On Asset Backed Indices [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2052-10	[1],[6]
Financial Derivatives - Assets [Member] | Short Credit Default Swap On Asset Backed Indices ABX.HE AAA 2006-2 Index [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure			Credit	[1],[3],[6]
Notional value			(62,842,000)	[1],[3],[6]
Range of expiration dates			2046-05	[1],[3],[6]
Derivative Assets			35,542,000	[1],[3],[6]
Financial Derivatives - Assets [Member] | Short Credit Default Swap On Asset Backed Indices Other [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure			Credit	[1],[3],[6]
Notional value			(19,800,000)	[1],[3],[6]
Derivative Assets			4,761,000	[1],[3],[6]
Financial Derivatives - Assets [Member] | Short Credit Default Swap On Asset Backed Indices Other [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates			2049-03	[1],[3],[6]
Financial Derivatives - Assets [Member] | Short Credit Default Swap On Asset Backed Indices Other [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates			2052-10	[1],[3],[6]
Financial Derivatives - Assets [Member] | Short Credit Default Swaps On Corporate Bond Indices [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure			Credit	[1],[3],[7]
Notional value			(106,500,000)	[1],[3],[7]
Range of expiration dates			2016-12	[1],[3],[7]
Derivative Assets			963,000	[1],[3],[7]
Financial Derivatives - Assets [Member] | Short Interest Rate Swaps [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Interest Rates	[1],[8]	Interest Rates	[1],[3],[8]
Notional value	(18,900,000)	[1],[8]	(25,000,000)	[1],[3],[8]
Range of expiration dates	2017-10	[1],[8]	2014-12	[1],[3],[8]
Derivative Assets	5,000	[1],[8]	27,000	[1],[3],[8]
Financial Derivatives - Assets [Member] | Swaps [Member]
Investment Holdings, Other than Securities [Line Items]
Derivative Assets	48,504,000	[1]	102,859,000	[1],[3]
Investment owned as a percentage of net assets	9.58%	[1]	27.73%	[1],[3]
Financial derivatives - assets, cost	65,860,000	[1]	118,281,000	[1],[3]
Financial Derivatives - Assets [Member] | Short Eurodollar Future [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure			Interest Rates	[1],[9]
Notional value			(147,000,000)	[1],[9]
Derivative Assets			12,000	[1],[9]
Financial Derivatives - Assets [Member] | Short Eurodollar Future [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates			2012-03	[1],[9]
Financial Derivatives - Assets [Member] | Short Eurodollar Future [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates			2013-09	[1],[9]
Financial Derivatives - Assets [Member] | Futures [Member]
Investment Holdings, Other than Securities [Line Items]
Derivative Assets			12,000	[1]
Investment owned as a percentage of net assets			0.00%	[1]
Financial Derivatives - Liabilities [Member]
Investment Holdings, Other than Securities [Line Items]
Fair Value	(15,212,000)	[1]	(27,040,000)	[1]
Investment owned as a percentage of net assets	(3.00%)	[1]	(7.29%)	[1]
Derivatives, proceeds	(13,171,000)	[1]	(9,636,000)	[1]
Financial Derivatives - Liabilities [Member] | Long Credit Default Swap On Asset Backed Indices [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Credit	[1],[2]	Credit	[1],[2]
Notional value	30,050,000	[1],[2]	22,615,000	[1],[2]
Fair Value	(12,751,000)	[1],[2]	(9,548,000)	[1],[2]
Derivatives, proceeds	(12,736,000)	[1],[2]	(9,636,000)	[1],[2]
Financial Derivatives - Liabilities [Member] | Long Credit Default Swap On Asset Backed Indices [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2049-12	[1],[2]	2036-06	[1],[2]
Financial Derivatives - Liabilities [Member] | Long Credit Default Swap On Asset Backed Indices [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2051-02	[1],[2]	2051-02	[1],[2]
Financial Derivatives - Liabilities [Member] | Long Interest Rate Swaps [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Interest Rates	[1],[4]
Notional value	2,500,000	[1],[4]
Fair Value	(32,000)	[1],[4]
Financial Derivatives - Liabilities [Member] | Long Interest Rate Swaps [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2022-11	[1],[4]
Financial Derivatives - Liabilities [Member] | Long Interest Rate Swaps [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2022-12	[1],[4]
Financial Derivatives - Liabilities [Member] | Short Credit Default Swap On Asset Backed Securities [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Credit	[1],[5]
Notional value	(3,000,000)	[1],[5]
Range of expiration dates	2035-03	[1],[5]
Fair Value	(1,000)	[1],[5]
Financial Derivatives - Liabilities [Member] | Short Credit Default Swap On Asset Backed Indices [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Credit	[1],[6]
Notional value	(7,792,000)	[1],[6]
Fair Value	(717,000)	[1],[6]
Financial Derivatives - Liabilities [Member] | Short Credit Default Swap On Asset Backed Indices [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2036-06	[1],[6]
Financial Derivatives - Liabilities [Member] | Short Credit Default Swap On Asset Backed Indices [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2037-12	[1],[6]
Financial Derivatives - Liabilities [Member] | Short Credit Default Swaps On Corporate Bond Indices [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Credit	[1],[7]
Notional value	(67,500,000)	[1],[7]
Range of expiration dates	2017-12	[1],[7]
Fair Value	(484,000)	[1],[7]
Financial Derivatives - Liabilities [Member] | Short Interest Rate Swaps [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Interest Rates	[1],[8]	Interest Rates	[1],[8]
Notional value	(220,000,000)	[1],[8]	(280,400,000)	[1],[8]
Fair Value	(1,092,000)	[1],[8]	(17,218,000)	[1],[8]
Financial Derivatives - Liabilities [Member] | Short Interest Rate Swaps [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2014-08	[1],[8]	2014-04	[1],[8]
Financial Derivatives - Liabilities [Member] | Short Interest Rate Swaps [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2022-11	[1],[8]	2021-12	[1],[8]
Financial Derivatives - Liabilities [Member] | Short Total Return Swaps [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Equity Market	[1],[10]	Equity Market	[1],[10]
Notional value	(18,737,000)	[1],[10]	(20,571,000)	[1],[10]
Range of expiration dates	2013-09	[1],[10]
Fair Value	(65,000)	[1],[10]	(274,000)	[1],[10]
Financial Derivatives - Liabilities [Member] | Short Total Return Swaps [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates			2012-09	[1],[10]
Financial Derivatives - Liabilities [Member] | Short Total Return Swaps [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates			2013-09	[1],[10]
Financial Derivatives - Liabilities [Member] | Swaps [Member]
Investment Holdings, Other than Securities [Line Items]
Fair Value	(15,142,000)	[1]	(27,040,000)	[1]
Investment owned as a percentage of net assets	(2.99%)	[1]	(7.29%)	[1]
Derivatives, proceeds	(13,171,000)	[1]	(9,636,000)	[1]
Financial Derivatives - Liabilities [Member] | Short Eurodollar Future [Member]
Investment Holdings, Other than Securities [Line Items]
Primary risk exposure	Interest Rates	[1],[9]
Notional value	(63,000,000)	[1],[9]
Fair Value	(70,000)	[1],[9]
Financial Derivatives - Liabilities [Member] | Short Eurodollar Future [Member] | Minimum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2013-03	[1],[9]
Financial Derivatives - Liabilities [Member] | Short Eurodollar Future [Member] | Maximum [Member]
Investment Holdings, Other than Securities [Line Items]
Range of expiration dates	2013-09	[1],[9]
Financial Derivatives - Liabilities [Member] | Futures [Member]
Investment Holdings, Other than Securities [Line Items]
Fair Value	$ (70,000)	[1]
Investment owned as a percentage of net assets	(0.01%)	[1]

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

[2] For long credit default swaps on asset-backed indices, the Company sold protection.

[3] The following table shows the Company’s swap assets by dealer as a percentage of shareholders’ equity:Dealer/Parent CompanyPercent ofShareholders’EquityAffiliates of Morgan Stanley8.15%Affiliates of Credit Suisse7.27%Affiliates of Deutsche Bank5.65%

[4] For long interest rate swap contracts, a floating rate is being paid and a fixed rate is being received.

[5] For short credit default swaps on asset-backed securities, the Company purchased protection.

[6] For short credit default swaps on asset-backed indices, the Company purchased protection.

[7] For short credit default swaps on corporate bond indices, the Company purchased protection.

[8] For short interest rate swap contracts, a fixed rate is being paid and a floating rate is being received.

[9] Every $1,000,000 in notional value represents one contract.

[10] Notional value represents number of underlying shares or par value times the closing price of the underlying security.