Employee Benefit Plans (Supplemental Retirement Programs) (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) investment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Deferred Compensation Plan
Defined Benefit Plan Disclosure [Line Items]
Maximum deferral of base salary	50.00%
Maximum deferral of incentive compensation bonuses	100.00%
Number of permitted investment alternatives | investment	3
Expenses associated with deferred compensation plan	$ 0.1	$ 0.8	$ 0.1
Deferred compensation liability	0.8	13.1
Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost SERP Restoration	1.2	1.3	$ 2.1
Benefit obligation SERP Restoration	$ 7.6	$ 7.6