Fair Value Measurements (Financial Instruments Recorded at Fair Value) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Cash and cash equivalents	$ 115.6	$ 193.8
Deferred compensation asset	2.4	3.2
Deferred compensation obligation	2.4	3.2
Fair Value, Inputs, Level 1 [Member]
Deferred compensation asset	2.4	3.2
Deferred compensation obligation	2.4	3.2
Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	0.0	0.0
Deferred compensation asset	0.0	0.0
Deferred compensation obligation	0.0	0.0
Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0.0	0.0
Deferred compensation asset	0.0	0.0
Deferred compensation obligation	$ 0.0	$ 0.0