Consolidated Condensed Schedule Of Investments (Repurchase Agreements) (Repurchase Agreements [Member], USD $) In Thousands, unless otherwise specified					9 Months Ended						12 Months Ended
	Sep. 30, 2013		Dec. 31, 2012		Sep. 30, 2013 JP Morgan Securities Inc Collateralized By Par Value $18,700 U.S. Treasury Note Coupon 2.00% Maturity Date 2023-02 [Member]		Sep. 30, 2013 JP Morgan Securities Inc Collateralized By Par Value $13,000 U.S. Treasury Note Coupon 1.75% Maturity Date 2016-05 [Member]		Sep. 30, 2013 Bank Of America Securities Collaterized By Par Value $10,000 US Treasury Note Coupon 1.13% Maturity Date 2019-12 [Member]		Dec. 31, 2012 Bank Of America Securities Collateralized By Par Value $13,000 U.S. Treasury Note, Coupon 1.75%, Maturity Date 2016-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount					$ 17,882	[1],[2]	$ 13,487	[1],[2]	$ 9,625	[1],[2]	$ 13,650	[1],[2]
Securities collateralized by par value					18,700	[1],[2]	13,000	[1],[2]	10,000	[1],[2]	13,000	[1],[2]
U.S. treasury note, coupon					2.00%	[1],[2]	1.75%	[1],[2]	1.13%	[1],[2]	1.75%	[1],[2]
Maturity date of securities					2023-02	[1],[2]	2016-05	[1],[2]	2019-12	[1],[2]	2016-05	[1],[2]
Description					J.P. Morgan Securities Inc. Collateralized by Par Value $18,700 U.S. Treasury Note, Coupon 2.00%, Maturity Date 2/23	[1],[2]	J.P. Morgan Securities Inc. Collateralized by Par Value $13,000 U.S. Treasury Note, Coupon 1.75%, Maturity Date 5/16	[1],[2]	J.P. Morgan Securities Inc. Collateralized by Par Value $10,000 U.S. Treasury Note, Coupon 1.13%, Maturity Date 12/19	[1],[2]	Bank of America SecuritiesCollateralized by Par Value $13,000US Treasury Note, Coupon 1.75%, Maturity Date 2016-05	[1],[2]
Rate					0.04%	[1],[2]	0.06%	[1],[2]	0.02%	[1],[2]	0.20%	[1],[2]
Investments maturity date					2013-10	[1],[2]	2013-10	[1],[2]	2013-10	[1],[2]	2013-01	[1],[2]
Fair value	40,994	[1],[2]	13,650	[1],[2]	17,882	[1],[2]	13,487	[1],[2]	9,625	[1],[2]	13,650	[1],[2]
Investment owned as a percentage of net assets	6.51%	[1],[2],[3]	2.70%	[1],[2],[3]
Repurchase agreements, cost	$ 40,994	[1],[2]	$ 13,650	[1],[2]

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

[2] In general, securities received pursuant to repurchase agreements were delivered to counterparties in short sale transactions.

[3] Classification percentages are based on Total Equity.