Profit Sharing Plan (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
401 (k) Profit Sharing Plan (Member)
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution amount	$ 0.1	$ 0.5	$ 0.5