Consolidated Condensed Schedule Of Investments (Repurchase Agreements) (Repurchase Agreements [Member], USD $) In Thousands, unless otherwise specified					6 Months Ended						12 Months Ended
	Jun. 30, 2012		Dec. 31, 2011		Jun. 30, 2012 Bank Of America Securities Collateralized By Par Value $15,000 U.S. Treasury Note, Coupon 0.25%, Maturity Date 2015-05 [Member]		Jun. 30, 2012 Bank Of America Securities Collateralized By Par Value $13,000 U.S. Treasury Note, Coupon 1.75%, Maturity Date 2016-05 [Member]		Jun. 30, 2012 Bank Of America Securities Collateralized By Par Value $8,000 U.S. Treasury Note, Coupon 0.63%, Maturity Date 2017-05 [Member]		Dec. 31, 2011 Bank of America Securities Collateralized By Par Value $15,000 U.S. Treasury Note, Coupon 1.75%, Maturity Date 2016-05 [Member]
Schedule of Investments [Line Items]
Current Principal/Notional Amount					$ 14,963	[1],[2]	$ 13,715	[1],[2]	$ 8,070	[1],[2]	$ 15,750	[1],[2]
Securities collateralized by par value					15,000	[1],[2]	13,000	[1],[2]	8,000	[1],[2]	15,000	[1],[2]
U.S. treasury note, coupon					0.25%	[1],[2]	1.75%	[1],[2]	0.63%	[1],[2]	1.75%	[1],[2]
Maturity date of securities					2015-05	[1],[2]	2016-05	[1],[2]	2017-05	[1],[2]	2016-05	[1],[2]
Description					Bank of America SecuritiesCollateralized by Par Value $15,000U.S. Treasury Note, Coupon 0.25%,Maturity Date 2015-05	[1],[2]	Bank of America SecuritiesCollateralized by Par Value $13,000U.S. Treasury Note, Coupon 1.75%,Maturity Date 2016-05	[1],[2]	Bank of America SecuritiesCollateralized by Par Value $8,000U.S. Treasury Note, Coupon 0.63%,Maturity Date 2017-05	[1],[2]	Bank of America SecuritiesCollateralized by Par Value $15,000U.S. Treasury Note, Coupon 1.75%,Maturity Date 2016-05	[1],[2]
Rate					0.14%	[1],[2]	0.18%	[1],[2]	(0.15%)	[1],[2]	0.01%	[1],[2]
Investments maturity date					2012-07	[1],[2]	2012-07	[1],[2]	2012-07	[1],[2]	2012-01	[1],[2]
Fair value	36,748	[1],[2]	15,750	[1],[2]	14,963	[1],[2]	13,715	[1],[2]	8,070	[1],[2]	15,750	[1],[2]
Repurchase agreements, cost	$ 36,748	[1],[2]	$ 15,750	[1],[2]
Investments owned as a percentage of net assets	9.30%	[1],[2]	4.24%	[1],[2]

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

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