Income Taxes (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Doubling bonus depreciation	100.00%
Doubling bonus depreciation, period	5 years
Additional depreciation			$ 5.0
Income tax benefit		$ 0.6
Expected effective income tax rate for the year	27.00%