Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Income Tax Contingency [Line Items]
Valuation allowance	$ 0.1		$ 0.1		$ 0.1
Effective income tax rate	28.20%	23.40%	24.90%	23.30%
Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Effective income tax rate, excluding income tax adjustment	24.70%		23.60%
Excess Windfall Tax Benefits [Member] | Income Taxes Payable [Member]
Income Tax Contingency [Line Items]
Out of period adjustment			$ (1.5)
Income Tax Expense [Member] | Excess Windfall Tax Benefits [Member]
Income Tax Contingency [Line Items]
Out of period adjustment	$ 1.6		$ 1.5