Goodwill and Intangible Assets (Schedule of Components of Intangible Assets) (Details) - Advisory Contracts [Member] - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 20,803	$ 20,803
Accumulated amortization	12,641	11,663
Net amount	$ 8,162	$ 9,140