Goodwill And Intangible Assets (Summary Of Intangible Assets) (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	$ 22.1
Finite-Lived Intangible Assets, Amortization Expense, Year Two	41.3
Finite-Lived Intangible Assets, Amortization Expense, Year Three	37.2
Gross Asset	827.9	$ 579.3
Accumulated Amortization	323.3	302.5
Net	504.6	276.8
Finite-Lived Intangible Assets, Net	504.6	276.8	$ 282.2
Finite-Lived Intangible Assets, Amortization Expense, Year Four	34.6
Finite-Lived Intangible Assets, Amortization Expense, Year Five	299.1
Intellectual Property Rights
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Asset	131.6	91.7
Accumulated Amortization	55.3	54.8
Net	76.3	36.9
Customer Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Asset	549.8	414.7
Accumulated Amortization	197.9	183.4
Net	351.9	231.3
Drawings
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Asset	11.1	11.1
Accumulated Amortization	10.4	10.4
Net	0.7	0.7
Other Intangible Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Asset	135.4	61.8
Accumulated Amortization	59.7	53.9
Net	$ 75.7	$ 7.9