Goodwill Impairment (Notes)	9 Months Ended
Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill Impairment	Goodwill Impairment At September 30, 2017, the Company had $531.9 million of goodwill on its consolidated balance sheet, all of which relates to the High Performance Materials & Components (HPMC) segment. Goodwill decreased $110.0 million at September 30, 2017 compared to December 31, 2016, resulting from a $114.4 million impairment charge in the HPMC segment offset by $4.4 million from the impact of foreign currency translation on goodwill denominated in functional currencies other than the U.S. dollar. The Company performs its annual goodwill impairment evaluations in the fourth quarter of each year. During the third quarter of 2017, the Company performed an interim goodwill impairment analysis on ATI Cast Products, a titanium investment casting business, due to impairment indicators including lower actual results versus projections. This reporting unit had a fair value that exceeded carrying value by 12% as a result of our 2016 annual goodwill impairment evaluation. For the 2017 interim impairment analysis, fair value was determined by using a quantitative assessment that used a discounted cash flow technique, which represents Level 3 unobservable information in the fair value hierarchy. As a result of the 2017 interim goodwill impairment evaluation, the Company determined that the fair value of the Cast Products business was significantly below the carrying value, including goodwill. This was primarily due to lower projected revenues, profitability and cash flows associated with revised expectations for the rate of operational improvement and profitability of this business based on current customer agreements. Consequently, during the third quarter of 2017, the Company recorded a $114.4 million pre-tax impairment charge to write-off all of the goodwill associated with ATI Cast Products, most of which was assigned from the Company’s 2011 Ladish acquisition that was not deductible for income tax purposes. This goodwill impairment charge was excluded from 2017 HPMC business segment results. Accumulated goodwill impairment losses as of September 30, 2017 and December 31, 2016 were $241.0 million and $126.6 million, respectively. Also during the third quarter of 2017, management concluded that the goodwill impairment at ATI Cast Products was an impairment indicator to evaluate the recoverability of other long-lived assets of this reporting unit, including property, plant, equipment, and intangible assets. No impairment was determined to exist in these long-lived assets as a result of this interim impairment test.

Goodwill Impairment

At September 30, 2017, the Company had $531.9 million of goodwill on its consolidated balance sheet, all of which relates to the High Performance Materials & Components (HPMC) segment. Goodwill decreased $110.0 million at September 30, 2017 compared to December 31, 2016, resulting from a $114.4 million impairment charge in the HPMC segment offset by $4.4 million from the impact of foreign currency translation on goodwill denominated in functional currencies other than the U.S. dollar.

The Company performs its annual goodwill impairment evaluations in the fourth quarter of each year. During the third quarter of 2017, the Company performed an interim goodwill impairment analysis on ATI Cast Products, a titanium investment casting business, due to impairment indicators including lower actual results versus projections. This reporting unit had a fair value that exceeded carrying value by 12% as a result of our 2016 annual goodwill impairment evaluation. For the 2017 interim impairment analysis, fair value was determined by using a quantitative assessment that used a discounted cash flow technique, which represents Level 3 unobservable information in the fair value hierarchy. As a result of the 2017 interim goodwill impairment evaluation, the Company determined that the fair value of the Cast Products business was significantly below the carrying value, including goodwill. This was primarily due to lower projected revenues, profitability and cash flows associated with revised expectations for the rate of operational improvement and profitability of this business based on current customer agreements. Consequently, during the third quarter of 2017, the Company recorded a $114.4 million pre-tax impairment charge to write-off all of the goodwill associated with ATI Cast Products, most of which was assigned from the Company’s 2011 Ladish acquisition that was not deductible for income tax purposes. This goodwill impairment charge was excluded from 2017 HPMC business segment results. Accumulated goodwill impairment losses as of September 30, 2017 and December 31, 2016 were $241.0 million and $126.6 million, respectively.

Also during the third quarter of 2017, management concluded that the goodwill impairment at ATI Cast Products was an impairment indicator to evaluate the recoverability of other long-lived assets of this reporting unit, including property, plant, equipment, and intangible assets. No impairment was determined to exist in these long-lived assets as a result of this interim impairment test.