Fair Value of Financial Instruments (Estimated Fair Values Of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Assets
Total return swap	$ 0	$ 1,650
Liabilities
Total return swap	1,287	0
Unsecured Debt	150,000	50,000
Investments [Member]
Assets
Investments	3,407,703	3,158,312
Secured Notes [Member]
Liabilities
Secured notes payable	140,000	140,000
Equity Contract [Member]
Liabilities
Equity contracts	$ 348	$ 140