Lines of Credit and Financing Arrangements (Outstanding Debt Obligations) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Short-Term Debt:
Total short-term debt	$ 3.8	$ 0.9
Current maturities of long-term debt:
Capital lease obligations	0.4	3.2
Debt issuance costs	(0.6)	(0.6)
Total current maturities of long-term debt	29.8	32.6
Long-Term Debt:
Capital lease obligations	11.9	11.9
Debt issuance costs	(3.9)	(4.4)
Total long-term debt	1,319.0	970.5
Total debt	1,352.6	1,004.0
Domestic Credit Facility [Member]
Current maturities of long-term debt:
Domestic credit facility and senior unsecured notes	30.0	30.0
Long-Term Debt:
Domestic credit facility and senior unsecured notes	671.0	337.0
Asset Securitization [Member]
Long-Term Debt:
Domestic credit facility and senior unsecured notes	290.0	276.0
Senior Unsecured Notes [Member]
Long-Term Debt:
Domestic credit facility and senior unsecured notes	350.0	350.0
Foreign Obligations [Member]
Short-Term Debt:
Total short-term debt	$ 3.8	$ 0.9