Summary of Significant Accounting Policies (Inventories) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Inventories	$ 343.5	$ 291.0

The amount of LIFO (last in first out) inventory present at the reporting date when inventory is also valued using different valuation methods.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6361739&loc=d3e7789-107766

Name:	us-gaap_LIFOInventoryAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant