Commitments and Contingencies - Summary of Financial Information for the Impact of Environmental Reserves and Recoveries (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Estimated Recoverable Amounts Under U.S. Government Contracts	$ 3.7	$ 3.8	$ 7.8	$ 7.7
Expense to Unaudited Condensed Consolidated Statement of Operations	1.4	0.9	2.8	1.7
Total Environmental Reserve Adjustments	$ 5.1	$ 4.7	$ 10.6	$ 9.4

Amount of expense for newly incurred environmental loss contingencies. Includes, but is not limited to, remediation expense and interest accretion.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 5.Y.Q2)
-URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751

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- Definition

Increase (decrease) in the accrual for environmental loss contingencies during the reporting period.

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- References

No definition available.

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- Definition

Amount of the estimated recovery from third parties recorded in the period for an individual site that reduces environmental remediation expense.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 10
-Subparagraph (d)(3)
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13237-110859

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13296-110859

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