Fair Value Measurements (Fair Value of Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets:
Deferred compensation assets	$ 8.9	$ 7.4
Foreign currency contracts	0.5	0.2
Total assets at fair value	9.4	7.6
Liabilities:
Contingent consideration	4.9	8.0
Deferred compensation liabilities	9.9	8.4
Interest rate swap contracts		1.0
Foreign currency contracts	5.1	1.6
Total liabilities at fair value	19.9	19.0
Other Financial Instruments [Abstract]
Long-term debt, fair value	201.5	228.3
Long-term debt	197.0	226.2
Level 1 [Member]
Assets:
Deferred compensation assets	8.9	7.4
Total assets at fair value	8.9	7.4
Liabilities:
Deferred compensation liabilities	9.9	8.4
Total liabilities at fair value	9.9	8.4
Level 2 [Member]
Assets:
Foreign currency contracts	0.5	0.2
Total assets at fair value	0.5	0.2
Liabilities:
Interest rate swap contracts		1.0
Foreign currency contracts	5.1	1.6
Total liabilities at fair value	5.1	2.6
Level 3 [Member]
Liabilities:
Contingent consideration	4.9	8.0
Total liabilities at fair value	$ 4.9	$ 8.0