Pensions and Other Postretirement Benefit Plans (Narrative) (Details) $ in Millions	Dec. 31, 2017 USD ($)
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued postretirement liability	$ 57.4
Percent of consolidated pension plan assets	42.00%
Percent of consolidated pension plan obligations	43.00%
Canada [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued postretirement liability	$ 1.1

Amount of liability for retirement benefits, classified as other.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(15))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(15))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Name:	us-gaap_OtherPostretirementBenefitsPayableCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant