XML 120 R106.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Business Segments (Details2) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Segment Reporting Other Significant Reconciling Item [Line Items] |  |  |
Depreciation and amortization | $ 160.8 | $ 170.3 | $ 189.9
Capital expenditures | 122.7 | 202.2 | 144.5
Operating Segments [Member] |  |  |
Segment Reporting Other Significant Reconciling Item [Line Items] |  |  |
Depreciation and amortization | 160.8 | 170.3 | 189.9
Capital expenditures | 122.7 | 202.2 | 144.5
Operating Segments [Member] | High Performance Materials & Components [Member] |  |  |
Segment Reporting Other Significant Reconciling Item [Line Items] |  |  |
Depreciation and amortization | 109.3 | 118.4 | 131.8
Capital expenditures | 62.7 | 89.9 | 75.8
Operating Segments [Member] | Flat Rolled Products [Member] |  |  |
Segment Reporting Other Significant Reconciling Item [Line Items] |  |  |
Depreciation and amortization | 45.6 | 48.8 | 55.6
Capital expenditures | 59.1 | 111.8 | 68.0
Operating Segments [Member] | Corporate [Member] |  |  |
Segment Reporting Other Significant Reconciling Item [Line Items] |  |  |
Depreciation and amortization | 5.9 | 3.1 | 2.5
Capital expenditures | $ 0.9 | $ 0.5 | $ 0.7

X
- Definition The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 + Details
Name: | us-gaap_DepreciationDepletionAndAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireProductiveAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_SegmentReportingOtherSignificantReconcilingItemLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=ati_HighPerformanceMaterialsComponentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=ati_FlatRolledProductsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=us-gaap_CorporateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |