Fair Value of Financial Instruments (Estimated Fair Values Of Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Liabilities
Total return swap	$ 6,059	$ 4,025
Liabilities, Fair Value Disclosure, Recurring	296,325	294,219
Level 2 [Member]
Liabilities
Liabilities, Fair Value Disclosure, Recurring	296,059	294,025
Secured Debt [Member] | Borrowings [Member]
Liabilities
Liabilities, Fair Value Disclosure, Recurring	140,000	140,000
Secured Debt [Member] | Borrowings [Member] | Level 2 [Member]
Liabilities
Liabilities, Fair Value Disclosure, Recurring	140,000
Unsecured Debt [Member] | Borrowings [Member]
Liabilities
Liabilities, Fair Value Disclosure, Recurring	150,000	150,000
Unsecured Debt [Member] | Borrowings [Member] | Level 2 [Member]
Liabilities
Liabilities, Fair Value Disclosure, Recurring	150,000	150,000
Equity Contract [Member]
Liabilities
Equity contracts	266	194
Investments [Member]
Assets
Investments	$ 3,348,386	3,403,822
Secured Debt [Member] | Secured Debt [Member] | Borrowings [Member] | Level 2 [Member]
Liabilities
Liabilities, Fair Value Disclosure, Recurring		$ 140,000