Basis of Presentation Basis of Presentation (Cash, Cash Equivalents, and Restricted Cash) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 85	$ 58	$ 1,747
Restricted cash included in Other assets	40,782	40,600	39,483	$ 39,300
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 40,867	$ 40,614	$ 41,230	$ 40,905