Fair Value Measurements (Summarized Information About Level 3 Fair Value Measurements) (Details) - Level 3 - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Convertible Preferred Securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value measurement with unobservable input	$ 7,154	$ 7,388	$ 3,294
Convertible Preferred Securities | Implied based on market prices
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value measurement with unobservable input	$ 7,154	7,388
Real Property | Third-Party Appraisal
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, fair value measurement with unobservable input		$ 29,347