Employee Benefit Plans (Supplemental Retirement Programs) (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) investment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 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	$ 0.8	$ 0.1	$ 1.4
Deferred compensation liability	13.1	16.4
Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost SERP Restoration	1.3	2.1	$ 3.0
Benefit obligation SERP Restoration	7.3	$ 9.3
Supplemental Life Plan
Defined Benefit Plan Disclosure [Line Items]
Additional death benefits, minimum range	0.4
Additional death benefits, maximum range	$ 2.0