Income Taxes (Rollforward of Valuation Allowances) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowance at beginning of the year	$ 1,147	$ 1,161
Release of Colorado net operating loss valuation allowance	(8)	0
Change in federal benefit tax rate - deferred	240	0
Expiration of state net operating losses	(33)	(14)
Valuation allowance at end of the year	$ 1,346	$ 1,147