Investments In Securities (Schedule of Equity Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, Cost	$ 32,055	$ 31,255
Equity Securities, Estimated Fair Value	53,959	48,489
Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, Cost	32,055	31,255
Equity Securities, Estimated Fair Value	$ 53,959	$ 48,489