Fair Value of Financial Instruments (Estimated Fair Values Of Financial Instruments) (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Liabilities
Total return swap	$ 1,564,000	$ 4,025,000
Unsecured Debt	150,000,000	150,000,000
Equity Contract [Member]
Liabilities
Equity contracts	51,000	194,000
Investments [Member]
Assets
Investments	3,359,767,000	3,403,822,000
Secured Notes [Member]
Liabilities
Secured notes payable	$ 140,000,000	$ 140,000,000