Employee Benefit Plans (Supplemental Retirement Programs) (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) investment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 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	$ 1.4	$ 1.0
Deferred compensation liability	$ 16.4	21.0
Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Years since benefit was last offered to employees	8 years
Net periodic benefit cost SERP Restoration	$ 2.1	3.0	$ 3.9
Benefit obligation SERP Restoration	$ 9.3	$ 12.3
Supplemental Life Plan
Defined Benefit Plan Disclosure [Line Items]
Years since benefit was last offered to employees	8 years
Additional death benefits, minimum range	$ 0.4
Additional death benefits, maximum range	$ 2.0