Income Taxes Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation Allowance [Line Items]
Deferred Tax Assets, Valuation Allowance	$ 26,674	$ 24,075	$ 19,315
State Net Operating losses [Member]
Valuation Allowance [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	1,964	(1,476)
Foreign Net Operating losses and Impairments [Member]
Valuation Allowance [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 635	$ 6,236