Employee Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Employee Benefits
Defined Contribution Plan, Employer Matching Contribution, Percent of Match			50.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay			6.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 0.5	$ 0.4	$ 1.0	$ 0.7
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	0.90%		0.90%		0.90%
Defined Benefit Plan, Benefit Obligation	$ 2.5		$ 2.5		$ 2.4
Deferred compensation plan assets	0.5		0.5
Deferred compensation plan liabilities	$ 0.5		$ 0.5