Income Taxes, Summary of Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets, Valuation Allowance [Roll Forward]
Valuation allowance for deferred tax assets, beginning of year	$ 0	$ 0
Increase (decrease) in current year	269	0
Valuation allowance for deferred tax assets, end of year	$ 269	$ 0