Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Additional tax expense			$ 9,607,000
Increase (decrease) in valuation allowance	$ (1,885,000)	$ 77,000	5,047,000
Unrecognized tax benefits	0	0	0
Income tax penalties and interest accrued	0	0	0
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	$ 0	$ 0	$ 0