Kaiser Aluminum (KALU) 10-Q 25 Oct 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Oct. 21, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	1-09447
Entity Registrant Name	KAISER ALUMINUM CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3030279
Entity Address, Address Line One	27422 Portola Parkway
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Foothill Ranch
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92610-2831
City Area Code	(949)
Local Phone Number	614-1740
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common stock, par value $0.01 per share
Trading Symbol	KALU
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		15,878,619
Entity Central Index Key	0000811596
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 172.1	$ 125.6
Short-term investments	25.3	36.7
Receivables:
Trade receivables, net	188.1	179.8
Other	26.1	25.6
Contract assets	46.1	54.9
Inventories	192.5	215.1
Prepaid expenses and other current assets	18.4	18.9
Total current assets	668.6	656.6
Property, plant and equipment, net	614.3	611.8
Operating lease assets	26.3	0
Deferred tax assets, net	6.3	35.9
Intangible assets, net	30.3	32.4
Goodwill	44	44
Other assets	36.5	38.6
Total	1,426.3	1,419.3
Current liabilities:
Accounts payable	93.8	121.4
Accrued salaries, wages and related expenses	31.9	40.1
Other accrued liabilities	50.1	44
Total current liabilities	175.8	205.5
Long-term portion of operating lease liabilities	25.6	0
Net liabilities of Salaried VEBA	32.8	32.4
Deferred tax liabilities	4.2	4.2
Long-term liabilities	65.4	66.4
Long-term debt	371.1	370.4
Total liabilities	674.9	678.9
Commitments and contingencies
Stockholders' equity:
Preferred stock, 5,000,000 shares authorized at both September 30, 2019 and December 31, 2018; no shares were issued and outstanding at September 30, 2019 and December 31, 2018	0	0
Common stock, par value $0.01, 90,000,000 shares authorized at both September 30, 2019 and at December 31, 2018; 22,550,827 shares issued and 15,900,956 shares outstanding at September 30, 2019; 22,471,705 shares issued and 16,234,603 shares outstanding at December 31, 2018	0.2	0.2
Additional paid in capital	1,061.5	1,059.3
Retained earnings	193	150.2
Treasury stock, at cost, 6,649,871 shares at September 30, 2019 and 6,237,102 shares at December 31, 2018, respectively	(460.1)	(420.5)
Accumulated other comprehensive loss	(43.2)	(48.8)
Total stockholders' equity	751.4	740.4
Total	$ 1,426.3	$ 1,419.3

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Stockholders' equity:
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	90,000,000	90,000,000
Common Stock, shares issued	22,550,827	22,471,705
Common stock, shares outstanding	15,900,956	16,234,603
Treasury stock, shares	6,649,871	6,237,102

Statements of Consolidated Inco

Statements of Consolidated Income (Unaudited) - USD ($) shares in Thousands, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales	$ 374.9			$ 393.1			$ 1,145.4	$ 1,196.5
Costs and expenses:
Cost of products sold, excluding depreciation and amortization and other items	298.6			323.3			917.2	983.4
Depreciation and amortization	12.3			11			36.3	32.4
Selling, general, administrative, research and development	23.3			23.9			75.7	73.9
Other operating charges, net	0			0			0.1	0.1
Total costs and expenses	334.2			358.2			1,029.3	1,089.8
Operating income	40.7			34.9			116.1	106.7
Other (expense) income:
Interest expense	(5.8)			(5.7)			(17.3)	(17)
Other (expense) income, net	(0.8)			0.7			(0.4)	0.3
Income before income taxes	34.1			29.9			98.4	90
Income tax provision	(8.7)			(8.2)			(25.8)	(21.9)
Net income	$ 25.4	$ 19.2	$ 28	$ 21.7	$ 20.7	$ 25.7	$ 72.6	$ 68.1
Net income per common share:
Basic (in dollars per share)	$ 1.59			$ 1.31			$ 4.52	$ 4.09
Diluted (in dollars per share)	$ 1.57			$ 1.29			$ 4.47	$ 4.03
Weighted-average number of common shares outstanding:
Basic (shares)	15,956			16,573			16,042	16,654
Diluted (shares)	16,125			16,783			16,235	16,882

Statements of Consolidated Comp

Statements of Consolidated Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 25.4	$ 21.7	$ 72.6	$ 68.1
Other comprehensive (loss) income, net of tax:
Defined benefit pension plan and Salaried VEBA	1.2	1.1	3.4	3.5
Available for sale securities	0.1	(0.2)	(0.2)	(0.5)
Cash flow hedges	(2.2)	(1.7)	2.4	(5.7)
Other comprehensive (loss) income, net of tax	(0.9)	(0.8)	5.6	(2.7)
Comprehensive income	$ 24.5	$ 20.9	$ 78.2	$ 65.4

Statements of Consolidated Stoc

Statements of Consolidated Stockholders' Equity (Unaudited) - USD ($) $ in Millions		Total	Common Stock	Additional Paid in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Stockholders' Equity [Roll Forward]
Cumulative-effect adjustment		$ 10.1			$ 10.5	$ 0	$ (0.4)
Adjusted balance		$ 756.4	$ 0.2	$ 1,055.9	96	(358.6)	(37.1)
Common Stock, Dividends, Per Share, Declared		$ 0.55
Beginning balance (shares) at Dec. 31, 2017			16,773,586
Beginning balance at Dec. 31, 2017		$ 746.3	$ 0.2	1,055.9	85.5	(358.6)	(36.7)
Stockholders' Equity [Roll Forward]
Net income		25.7			25.7
Other comprehensive income (loss), net of tax		(8.3)					(8.3)
Issuance of common shares to employees upon vesting of restricted stock units and performance shares (shares)			135,134
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (shares)			(68,029)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(6.9)		(6.9)
Repurchase of common stock (shares)	[1]		(58,155)
Repurchase of common stock1	[1]	(6.1)				(6.1)
Cash dividends on common stock and restricted shares and dividend equivalents on restricted stock units and performance shares2	[2]	(10)			(10)
Amortization of unearned equity compensation		2.8		2.8
Ending balance (shares) at Mar. 31, 2018			16,782,536
Ending balance at Mar. 31, 2018		753.6	$ 0.2	1,051.8	111.7	(364.7)	(45.4)
Beginning balance (shares) at Dec. 31, 2017			16,773,586
Beginning balance at Dec. 31, 2017		746.3	$ 0.2	1,055.9	85.5	(358.6)	(36.7)
Stockholders' Equity [Roll Forward]
Net income		68.1
Ending balance (shares) at Sep. 30, 2018			16,547,237
Ending balance at Sep. 30, 2018		$ 762.5	$ 0.2	1,057.4	135.6	(390.9)	(39.8)
Common Stock, Dividends, Per Share, Declared		$ 0.55
Beginning balance (shares) at Mar. 31, 2018			16,782,536
Beginning balance at Mar. 31, 2018		$ 753.6	$ 0.2	1,051.8	111.7	(364.7)	(45.4)
Stockholders' Equity [Roll Forward]
Net income		20.7			20.7
Other comprehensive income (loss), net of tax		6.4					6.4
Issuance of non-vested shares to non-employee directors (shares)			9,009
Issuance of common shares to non-employee directors (shares)			1,954
Issuance of common shares to non-employee directors		0.2		0.2
Issuance of common shares to employees upon vesting of restricted stock units and performance shares (shares)			82
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (shares)			(95)
Repurchase of common stock (shares)	[1]		(127,545)
Repurchase of common stock1	[1]	(13.3)				(13.3)
Cash dividends on common stock and restricted shares and dividend equivalents on restricted stock units and performance shares2	[2]	(9.3)			(9.3)
Amortization of unearned equity compensation		2.7		2.7
Ending balance (shares) at Jun. 30, 2018			16,665,941
Ending balance at Jun. 30, 2018		$ 761	$ 0.2	1,054.7	123.1	(378)	(39)
Common Stock, Dividends, Per Share, Declared		$ 0.55
Stockholders' Equity [Roll Forward]
Net income		$ 21.7			21.7
Other comprehensive income (loss), net of tax		(0.8)					(0.8)
Issuance of common shares to employees upon vesting of restricted stock units and performance shares (shares)			78
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (shares)			(42)
Repurchase of common stock (shares)	[1]		(118,740)
Repurchase of common stock1	[1]	(12.9)				(12.9)
Cash dividends on common stock and restricted shares and dividend equivalents on restricted stock units and performance shares2	[2]	(9.2)			(9.2)
Amortization of unearned equity compensation		2.7		2.7
Ending balance (shares) at Sep. 30, 2018			16,547,237
Ending balance at Sep. 30, 2018		$ 762.5	$ 0.2	1,057.4	135.6	(390.9)	(39.8)
Common Stock, Dividends, Per Share, Declared		$ 0.60
Beginning balance (shares) at Dec. 31, 2018		16,234,603	16,234,603
Beginning balance at Dec. 31, 2018		$ 740.4	$ 0.2	1,059.3	150.2	(420.5)	(48.8)
Stockholders' Equity [Roll Forward]
Net income		28			28
Other comprehensive income (loss), net of tax		9.7					9.7
Issuance of common shares to employees upon vesting of restricted stock units and performance shares (shares)			122,309
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (shares)			(46,388)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(5)		(5)
Repurchase of common stock (shares)	[3]		(175,977)
Repurchase of common stock1	[3]	(17.4)				(17.4)
Cash dividends on common stock and restricted shares and dividend equivalents on restricted stock units and performance shares2	[4]	(10.2)			(10.2)
Amortization of unearned equity compensation		2.4		2.4
Ending balance (shares) at Mar. 31, 2019			16,134,547
Ending balance at Mar. 31, 2019		$ 747.9	$ 0.2	1,056.7	168	(437.9)	(39.1)
Beginning balance (shares) at Dec. 31, 2018		16,234,603	16,234,603
Beginning balance at Dec. 31, 2018		$ 740.4	$ 0.2	1,059.3	150.2	(420.5)	(48.8)
Stockholders' Equity [Roll Forward]
Net income		$ 72.6
Ending balance (shares) at Sep. 30, 2019		15,900,956	15,900,956
Ending balance at Sep. 30, 2019		$ 751.4	$ 0.2	1,061.5	193	(460.1)	(43.2)
Common Stock, Dividends, Per Share, Declared		$ 0.60
Beginning balance (shares) at Mar. 31, 2019			16,134,547
Beginning balance at Mar. 31, 2019		$ 747.9	$ 0.2	1,056.7	168	(437.9)	(39.1)
Stockholders' Equity [Roll Forward]
Net income		19.2			19.2
Other comprehensive income (loss), net of tax		(3.2)					(3.2)
Issuance of non-vested shares to non-employee directors (shares)			11,850
Issuance of common shares to non-employee directors (shares)			2,850
Issuance of common shares to non-employee directors		0.3		0.3
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (shares)			(12,395)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(1.2)		(1.2)
Repurchase of common stock (shares)	[3]		(108,177)
Repurchase of common stock1	[3]	(10.2)				(10.2)
Cash dividends on common stock and restricted shares and dividend equivalents on restricted stock units and performance shares2	[4]	(9.9)			(9.9)
Amortization of unearned equity compensation		3.4		3.4
Ending balance (shares) at Jun. 30, 2019			16,028,675
Ending balance at Jun. 30, 2019		746.3	$ 0.2	1,059.2	177.3	(448.1)	(42.3)
Stockholders' Equity [Roll Forward]
Net income		25.4			25.4
Other comprehensive income (loss), net of tax		(0.9)					(0.9)
Issuance of non-vested shares to non-employee directors (shares)			896
Repurchase of common stock (shares)	[3]		(128,615)
Repurchase of common stock1	[3]	(12)				(12)
Cash dividends on common stock and restricted shares and dividend equivalents on restricted stock units and performance shares2	[4]	(9.7)			(9.7)
Amortization of unearned equity compensation		$ 2.3		2.3
Ending balance (shares) at Sep. 30, 2019		15,900,956	15,900,956
Ending balance at Sep. 30, 2019		$ 751.4	$ 0.2	$ 1,061.5	$ 193	$ (460.1)	$ (43.2)
[1]	Weighted-average repurchase price (dollars per share) for the quarters ended March 31, 2018, June 30, 2018 and September 30, 2018 was $104.50 , $104.74 and $108.07 , respectively.
[2]	Dividends declared per common share were $0.55 during each of the quarters ended March 31, 2018, June 30, 2018 and September 30, 2018 .
[3]	Weighted-average repurchase price (dollars per share) for the quarters ended March 31, 2019, June 30, 2019 and September 30, 2019 was $98.55 , $95.00 and $92.95 , respectively. At September 30, 2019 , $108.9 million remained available to repurchase our common shares pursuant to the stock repurchase program.
[4]	Dividends declared per common share were $0.60 during each of the quarters ended March 31, 2019, June 30, 2019 and September 30, 2019 .

Statements of Consolidated St_2

Statements of Consolidated Stockholders' Equity (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Weighted average repurchase price (in dollars per share)	$ 92.95	$ 95	$ 98.55	$ 108.07	$ 104.74	$ 104.50
Repurchase amount remaining	$ 108.9
Cash dividends declared (in dollars per share)		$ 0.60	$ 0.60	$ 0.55	$ 0.55	$ 0.55

Statement of Consolidated Cash

Statement of Consolidated Cash Flows (Unaudited) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income		$ 72.6	$ 68.1
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property, plant and equipment		34.2	31.3
Amortization of definite-lived intangible assets		2.1	1.1
Amortization of debt discount and debt issuance costs		0.9	0.8
Deferred income taxes		27.8	27.4
Non-cash equity compensation		8.4	8.4
Gain on disposition of available for sale securities		(0.6)	(2.4)
Non-cash asset impairment charge		0.1	0.1
Gain on disposition of property, plant and equipment		(0.1)	(0.2)
Other non-cash changes in assets and liabilities		9.3	20.2
Changes in operating assets and liabilities:
Trade and other receivables		(8.8)	(35.7)
Contract assets		8.8	4.6
Inventories		22.6	(25.6)
Prepaid expenses and other current assets		(1.7)	(1.6)
Accounts payable		(21.9)	31.1
Accrued liabilities		(3.3)	(1)
Annual variable cash contributions to VEBAs		(2.1)	(15.7)
Long-term assets and liabilities, net		5.6	1.6
Net cash provided by operating activities		153.9	112.5
Cash flows from investing activities
Capital expenditures		(40.7)	(53.1)
Purchase of available for sale securities		(56.3)	(111.9)
Purchase of equity securities		(0.7)	(0.9)
Proceeds from disposition of available for sale securities		68.2	208.7
Cash payment for acquisition of Imperial Machine & Tool Co., net of cash received		0	(43.3)
Proceeds from disposition of property, plant and equipment		0.2	0.6
Net cash (used in) provided by investing activities	[1]	(29.3)	0.1
Cash flows from financing activities
Repayment of finance lease		(1.1)	(0.5)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(6.2)	(6.9)
Repurchase of common stock		(40.6)	(31.9)
Cash dividends and dividend equivalents paid		(29.8)	(28.5)
Net cash used in financing activities	[1]	(77.7)	(67.8)
Net increase in cash, cash equivalents and restricted cash during the period		46.9	44.8
Cash, cash equivalents and restricted cash at beginning of period		139.6	64.3
Cash, cash equivalents and restricted cash at end of period		$ 186.5	$ 109.1
[1]	See Note 12 for supplemental cash flow information.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies This Quarterly Report on Form 10-Q (this "Report") should be read in conjunction with the Company's Annual Report on Form 10-K for the year ended December 31, 2018 . Unless the context otherwise requires, references in these notes to interim consolidated financial statements - unaudited to "Kaiser Aluminum Corporation," "we," "us," "our," "the Company" and "our Company" refer collectively to Kaiser Aluminum Corporation and its subsidiaries. Organization and Nature of Operations. Kaiser Aluminum Corporation specializes in the production of semi-fabricated specialty aluminum mill products, such as aluminum plate and sheet and extruded and drawn products, for the following end market applications: aerospace and high strength ("Aero/HS products"), automotive ("Automotive Extrusions"), general engineering ("GE products") and other industrial ("Other products"). Our business is organized into one operating segment. See Note 13 for additional information regarding our business, product and geographical area information and concentration of risk. Principles of Consolidation and Basis of Presentation. The accompanying unaudited consolidated financial statements include the accounts of our wholly owned subsidiaries and are prepared in accordance with United States generally accepted accounting principles ("GAAP") and the rules and regulations of the Securities and Exchange Commission ("SEC") applicable for interim periods and, therefore, do not include all information and footnotes required by GAAP for complete financial statements. In management's opinion, all adjustments (which include normal recurring adjustments) considered necessary for a fair presentation have been included. The results of operations for our interim periods are not necessarily indicative of the results of operations that may be achieved for the entire 2019 fiscal year. The financial information as of December 31, 2018 is derived from our audited consolidated financial statements and footnotes included in our Annual Report on Form 10-K for the year ended December 31, 2018 . Use of Estimates in the Preparation of Financial Statements. The preparation of financial statements in accordance with GAAP requires the use of estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities known to exist as of the date the financial statements are published and the reported amounts of revenues and expenses during the reporting period. Uncertainties with respect to such estimates and assumptions are inherent in the preparation of our consolidated financial statements; accordingly, it is possible that the actual results could differ from these estimates and assumptions, which could have a material effect on the reported amounts of our consolidated financial position and results of operations. Fair Value Measurements. We apply the fair value hierarchy established by GAAP for the recognition and measurement of certain financial assets and liabilities. An asset or liability's fair value classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. In determining fair value, we utilize valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible and consider counterparty risk in our assessment of fair value. We also review the underlying inputs that are significant to the fair value measurement of financial instruments to determine if a transfer among hierarchy levels is appropriate. We historically have not had significant transfers into or out of each hierarchy level. Financial assets and liabilities that we measure at fair value each period include our derivative instruments, equity investments related to our deferred compensation plan and debt investment securities classified as available for sale securities (see Note 4 and Note 5 ). Additionally, we measure at fair value once each year at December 31 our Canadian defined benefit pension plan and the plan assets of the Salaried VEBA (defined in Note 4 ). In determining the fair value of the plan assets at an annual period end, we utilize primarily the results of valuations supplied by the investment advisors responsible for managing the assets of each plan, which we independently review for reasonableness. We record our remaining financial assets and liabilities at carrying value. For a majority of our non-financial assets and liabilities, which include goodwill, intangible assets, inventories and property, plant and equipment, we are not required to measure their fair value on a recurring basis. However, if certain triggering events occur (or at least annually for goodwill), an evaluation of the affected non-financial asset or liability will be required, which could result in a reduction to the carrying amount of such asset or liability. None of our non-financial assets and liabilities subject to fair value assessments on a non-recurring basis required a material adjustment to the carrying amount of such assets and liabilities for the quarter and nine months ended September 30, 2019 . Inventories. Inventories are stated at the lower of cost or market value. Finished products, work-in-process and raw material inventories are stated on the last-in, first-out ("LIFO") basis. At September 30, 2019 and December 31, 2018 , the current cost of our inventory exceeded its stated LIFO value by $17.5 million and $31.7 million , respectively. Other inventories are stated on the first-in, first-out basis and consist of operating supplies, which are materials and supplies to be consumed during the production process. Inventory costs consist of material, labor and manufacturing overhead, including depreciation. Abnormal costs, such as idle facility expenses, freight, handling costs and spoilage, are accounted for as current period charges (see Note 2 for the components of inventories). Replacement Parts. Replacement parts consist of preventative maintenance and capital spare parts, which are stated on the first-in, first-out basis. Replacement parts are recorded within Prepaid expenses and other current assets or Other assets depending on whether or not the expected utilization of the replacement parts is to occur within the current operating cycle. Property, Plant and Equipment, Net. Property, plant and equipment, net, is recorded at cost and includes construction in progress (see Note 2 ). Interest related to the construction of qualifying assets is capitalized as part of the construction costs. The amount of interest expense capitalized as construction in progress was $0.4 million for each of the quarters ended September 30, 2019 and September 30, 2018 . The amount of interest expense capitalized as construction in progress was $1.3 million for each of the nine months ended September 30, 2019 and September 30, 2018 . Depreciation is computed using the straight-line method at rates based on the estimated useful lives of the various classes of assets. Finance lease assets and leasehold improvements are depreciated on a straight-line basis over the shorter of the estimated useful lives of the assets or the lease term. We classify assets as held for sale only when an asset is being actively marketed and expected to sell within 12 months. Assets held for sale are initially measured at the lesser of the assets' carrying amount and the fair value less costs to sell. Derivative Financial Instruments. Consistent with guidelines established by management and approved by our Board of Directors, we use derivative financial instruments to mitigate our exposure to changes in the market price of aluminum, alloying metals and energy, and, to a lesser extent, to foreign currency exchange rates. We do not use derivative financial instruments for trading or other speculative purposes. Hedging transactions are executed centrally on behalf of all of our operations to minimize transaction costs, monitor consolidated net exposures and allow for increased responsiveness to changes in market factors. We reflect the fair value of all of our derivative instruments on our Consolidated Balance Sheets (see Note 5 ). The fair value of hedges settling within one year is included in Prepaid expenses and other current assets or Other accrued liabilities. The fair value of hedges settling beyond one year is included in Other assets or Long-term liabilities. We designate our aluminum and energy derivatives and our forward swap contracts for zinc and copper ("Alloying Metals") used in our fabrication operations as cash flow hedges. Unrealized gains and losses associated with our cash flow hedges are deferred in Other comprehensive (loss) income, net of tax, and reclassified to Cost of products sold, excluding depreciation and amortization and other items ("COGS") when such hedges settle (see Note 5 ). Self Insurance of Workers' Compensation and Employee Healthcare Liabilities . We self-insure the majority of the costs of workers' compensation benefits and employee healthcare benefits and rely on insurance coverage to protect us from large losses on individual claims. Workers' compensation liabilities are based on a combination of estimates for: (i) incurred-but-not-reported claims and (ii) the ultimate expense of incurred claims. Such estimates are based on judgment, using our historical claims data and information and analysis provided by actuarial and claims advisors, our insurance carriers and other professionals. Our undiscounted workers' compensation liabilities were estimated at $28.0 million and $27.6 million as of September 30, 2019 and December 31, 2018 , respectively. However, we accounted for our workers' compensation accrued liabilities on a discounted basis (see Note 2 ), using a discount rate of 1.75% and 3.00% at September 30, 2019 and December 31, 2018 , respectively. Accrued liabilities for employee healthcare benefits, which are estimates of unpaid incurred medical and prescription drug costs as provided by our healthcare administrators, were $3.3 million and $3.6 million as of September 30, 2019 and December 31, 2018 , respectively. Short-Term Incentive Plans ("STI Plans"). We have annual short-term incentive compensation plans for senior management and certain other employees payable at our election in cash, shares of common stock or a combination of cash and shares of common stock. Amounts earned under STI Plans are based on our adjusted earnings before interest, taxes, depreciation and amortization ("Adjusted EBITDA"), modified for certain safety, quality, delivery, cost and individual performance factors. The Adjusted EBITDA targets are determined based on the return on adjusted net assets. Most of our production facilities have similar programs for both hourly and salaried employees. As of September 30, 2019 , we had a liability of $6.4 million recorded within Accrued salaries, wages and related expenses for estimated probable future payments relating to the nine month performance period of our 2019 STI Plan. Long-Term Incentive Programs. Executive officers and other key employees of the Company, as well as non-employee directors of the Company, are eligible to participate in the Kaiser Aluminum Corporation 2016 Equity and Incentive Compensation Plan approved by stockholders on May 26, 2016 ("2016 Plan"). At September 30, 2019 , 481,282 shares were available for awards under the 2016 Plan. We issue new shares of our common stock upon vesting under the 2016 Plan. Adoption of New Accounting Pronouncements ASU No. 2016-02, Leases (Topic 842): Amendments to the Financial Accounting Standards Board Accounting Standards Codification ("ASU 2016-02"), was issued in February 2016 (with amendments issued in 2018) and requires lessees to recognize a right-of-use asset and a lease liability for virtually all of their leases (other than leases that meet the definition of a short-term lease). For income statement purposes, a dual model was retained, requiring leases to be classified as either operating or finance. Operating leases will result in straight-line expense (similar to operating leases under the previous guidance) while finance leases will result in a front-loaded expense pattern (similar to capital leases under the previous guidance). We adopted ASU 2016-02 and its subsequent amendments (together "ASC 842") during the quarter ended March 31, 2019 using the transition approach provided for under ASU No. 2018-11, Leases (Topic 842): Targeted Improvements , which allowed us to apply the new lease standard as of January 1, 2019, rather than the beginning of the earliest period presented. We elected the package of practical expedients, which permitted us to: (i) not reassess whether any of our contracts contained leases; (ii) carry forward the historical lease classification of our existing leases; and (iii) not reassess initial direct costs for our existing leases. We did not elect to apply the hindsight practical expedient when determining lease term and assessing impairment of right-of-use assets. Due to our adoption of ASC 842, we recorded an operating lease right-of-use asset of $29.0 million , a current operating lease liability of $4.1 million and a long-term operating lease liability of $27.4 million on our Consolidated Balance Sheets as of January 1, 2019. There was no cumulative-effect adjustment to Retained earnings required. The standard did not materially impact our consolidated net earnings and had no impact on cash flows. Comparative information in this Report has not been adjusted and continues to be reported under the previous lease accounting rules. See Note 3 for details of the significant changes and quantitative impacts of the changes, as well as other required disclosures related to our adoption of ASC 842. There were no material impacts on our consolidated financial statements resulting from our adoption during the nine months ended September 30, 2019 of: (i) ASU No. 2018-07, Compensation-Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting; (ii) ASU No. 2018-08, Not-for-Profit Entities (Topic 958): Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made; and (iii) ASU No. 2019-07, Codification Updates to SEC Sections: Amendments to SEC Paragraphs Pursuant to SEC Final Rule Releases No. 33-10532, Disclosure Update and Simplification, and Nos. 33-10231 and 33-10442, Investment Company Reporting Modernization, and Miscellaneous Updates. Accounting Pronouncements Issued But Not Yet Adopted ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"), was issued in June 2016. Under ASU 2016-13, existing guidance on reporting credit losses for trade and other receivables and available for sale debt securities will be replaced with a new forward-looking "expected loss" model that generally will result in the earlier recognition of allowances for losses. We are currently in the process of evaluating the impact of adopting ASU 2016-13 in 2020, but do not expect it to have a material impact on our consolidated financial statements. ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract ("ASU 2018-15"), was issued in August 2018. Under ASU 2018-15, requirements for capitalizing implementation costs incurred in a hosting arrangement (cloud computing) that is a service contract are to be aligned with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. We are currently in the process of evaluating the impact of adopting ASU 2018-15 in 2020, but do not expect it to have a material impact on our consolidated financial statements.

Supplemental Balance Sheet Info

Supplemental Balance Sheet Information	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Balance Sheet Information	Supplemental Balance Sheet Information September 30, 2019 December 31, 2018 (In millions of dollars) Cash and Cash Equivalents Cash and money market funds $ 29.3 $ 22.9 Commercial paper 142.8 102.7 Total $ 172.1 $ 125.6 Trade Receivables, Net Billed trade receivables $ 188.9 $ 179.5 Unbilled trade receivables — 1.1 Trade receivables, gross 188.9 180.6 Allowance for doubtful receivables (0.8 ) (0.8 ) Trade receivables, net $ 188.1 $ 179.8 Inventories Finished products $ 41.4 $ 48.0 Work-in-process 80.5 85.6 Raw materials 63.7 75.0 Operating supplies 6.9 6.5 Total $ 192.5 $ 215.1 Property, Plant and Equipment, Net Land and improvements $ 21.4 $ 21.4 Buildings and leasehold improvements 99.2 97.0 Machinery and equipment 797.9 755.6 Construction in progress 35.4 43.6 Property, plant and equipment, gross 953.9 917.6 Accumulated depreciation (341.2 ) (307.4 ) Assets held for sale 1.6 1.6 Property, plant and equipment, net $ 614.3 $ 611.8 Other Accrued Liabilities Uncleared cash disbursements $ 3.7 $ 4.8 Accrued income taxes and taxes payable 8.0 6.5 Accrued annual contribution to Salaried VEBA — 2.1 Accrued interest 8.4 2.9 Accrued environmental – Note 7 4.3 2.6 Other – Note 3 and Note 5 25.7 25.1 Total $ 50.1 $ 44.0 September 30, 2019 December 31, 2018 (In millions of dollars) Long-Term Liabilities Workers' compensation accruals $ 26.9 $ 24.6 Long-term environmental accrual – Note 7 12.2 14.3 Other long-term liabilities 26.3 27.5 Total $ 65.4 $ 66.4

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	Leases We determine whether an agreement is a lease at inception. We have operating and finance leases for equipment and real estate that primarily have fixed lease payments. Our leases have remaining lease terms of approximately one to 15 years , some of which may include options to extend the lease for up to 20 years , and some of which may include options to terminate the lease within one year . None of our options to extend or terminate are reasonably certain of being exercised, and are therefore not included in our determination of lease assets and liabilities. Short-term leases with an initial term of 12 months or less are not recorded on our Consolidated Balance Sheets. As most of our leases do not provide an implicit rate, we use information available at the lease commencement date in determining an incremental borrowing rate when calculating our operating lease assets and operating lease liabilities. In determining the inputs to the incremental borrowing rate calculation, we make judgments about the value of the leased asset, our credit rating and the lease term, including the probability of our exercising options to extend or terminate the underlying lease. Additionally, we make judgments around contractual asset substitution rights in determining whether a contract contains a lease. We have lease agreements with lease and non-lease components, which are generally accounted for separately. These non-lease components include items such as common area maintenance, taxes and insurance for our real estate leases, as well as maintenance charges related to our equipment leases. We have, however, applied the practical expedient within ASU 2016-02 to not separate lease and non-lease components to our embedded supply system equipment leases and have therefore accounted for both lease and non-lease components in determining the lease assets and liabilities. Many of our equipment leases contain clauses that require us to return the equipment with certain functionality intact. We account for these costs as residual value guarantees when the guarantee becomes probable of being owed. Our lease agreements do not contain any material restrictive covenants. The following table presents lease terms and discount rates as of September 30, 2019 : Finance Leases Operating Leases Weighted-average lease term (in years): 6.0 10.5 Weighted-average discount rate: 4.5 % 5.9 % The following table summarizes the classification of lease assets and lease liabilities on our Consolidated Balance Sheet as of the period presented (in millions of dollars): Leases Classification September 30, 2019 Assets Operating lease assets Operating lease assets $ 26.3 Finance lease assets Property, plant and equipment, net 6.8 Total lease assets $ 33.1 Liabilities Current: Operating lease liabilities Other accrued liabilities $ 3.9 Finance lease liabilities Other accrued liabilities 1.2 Non-current: Operating lease liabilities Long-term portion of operating lease liabilities 25.6 Finance lease liabilities Long-term liabilities 5.6 Total lease liabilities $ 36.3 The following table summarizes the components of lease cost on our Statements of Consolidated Income for the periods presented (in millions of dollars): Lease Cost Quarter Ended September 30, 2019 Nine Months Ended September 30, 2019 Operating lease cost $ 1.8 $ 5.6 Short-term lease cost 0.3 0.8 Finance lease cost: Amortization of leased assets 0.5 1.2 Interest on lease liabilities — 0.2 Total lease cost $ 2.6 $ 7.8 The following table presents the maturity of our lease liabilities as of September 30, 2019 (in millions of dollars): Maturity of Lease Liabilities Finance Leases Operating Leases Remainder of 2019 $ 0.4 $ 1.3 2020 1.6 5.2 2021 1.4 4.4 2022 1.2 3.6 2023 1.1 3.4 2024 0.7 3.3 2025 and thereafter 1.4 18.9 Total minimum lease payments $ 7.8 $ 40.1 Less: interest (1.0 ) (10.6 ) Present value $ 6.8 $ 29.5 The following table presents minimum rental commitments at December 31, 2018 (in millions of dollars): Year Ended December 31, Finance Leases Operating Leases 2019 $ 1.7 $ 6.1 2020 1.4 3.7 2021 1.2 2.8 2022 1.1 2.4 2023 1.0 2.2 2024 and thereafter 1.8 20.8 Total minimum lease payments $ 8.2 $ 38.0 Less: interest (1.2 ) Present value 1 $ 7.0 _________________________ 1. Of the $7.0 million in finance lease obligations as of December 31, 2018, $1.4 million was included in Other accrued liabilities and $5.6 million was included in Long-term liabilities. Assets recorded under finance leases and the accumulated amortization thereon were $8.3 million and $1.3 million , respectively, as of December 31, 2018.
Leases	Leases We determine whether an agreement is a lease at inception. We have operating and finance leases for equipment and real estate that primarily have fixed lease payments. Our leases have remaining lease terms of approximately one to 15 years , some of which may include options to extend the lease for up to 20 years , and some of which may include options to terminate the lease within one year . None of our options to extend or terminate are reasonably certain of being exercised, and are therefore not included in our determination of lease assets and liabilities. Short-term leases with an initial term of 12 months or less are not recorded on our Consolidated Balance Sheets. As most of our leases do not provide an implicit rate, we use information available at the lease commencement date in determining an incremental borrowing rate when calculating our operating lease assets and operating lease liabilities. In determining the inputs to the incremental borrowing rate calculation, we make judgments about the value of the leased asset, our credit rating and the lease term, including the probability of our exercising options to extend or terminate the underlying lease. Additionally, we make judgments around contractual asset substitution rights in determining whether a contract contains a lease. We have lease agreements with lease and non-lease components, which are generally accounted for separately. These non-lease components include items such as common area maintenance, taxes and insurance for our real estate leases, as well as maintenance charges related to our equipment leases. We have, however, applied the practical expedient within ASU 2016-02 to not separate lease and non-lease components to our embedded supply system equipment leases and have therefore accounted for both lease and non-lease components in determining the lease assets and liabilities. Many of our equipment leases contain clauses that require us to return the equipment with certain functionality intact. We account for these costs as residual value guarantees when the guarantee becomes probable of being owed. Our lease agreements do not contain any material restrictive covenants. The following table presents lease terms and discount rates as of September 30, 2019 : Finance Leases Operating Leases Weighted-average lease term (in years): 6.0 10.5 Weighted-average discount rate: 4.5 % 5.9 % The following table summarizes the classification of lease assets and lease liabilities on our Consolidated Balance Sheet as of the period presented (in millions of dollars): Leases Classification September 30, 2019 Assets Operating lease assets Operating lease assets $ 26.3 Finance lease assets Property, plant and equipment, net 6.8 Total lease assets $ 33.1 Liabilities Current: Operating lease liabilities Other accrued liabilities $ 3.9 Finance lease liabilities Other accrued liabilities 1.2 Non-current: Operating lease liabilities Long-term portion of operating lease liabilities 25.6 Finance lease liabilities Long-term liabilities 5.6 Total lease liabilities $ 36.3 The following table summarizes the components of lease cost on our Statements of Consolidated Income for the periods presented (in millions of dollars): Lease Cost Quarter Ended September 30, 2019 Nine Months Ended September 30, 2019 Operating lease cost $ 1.8 $ 5.6 Short-term lease cost 0.3 0.8 Finance lease cost: Amortization of leased assets 0.5 1.2 Interest on lease liabilities — 0.2 Total lease cost $ 2.6 $ 7.8 The following table presents the maturity of our lease liabilities as of September 30, 2019 (in millions of dollars): Maturity of Lease Liabilities Finance Leases Operating Leases Remainder of 2019 $ 0.4 $ 1.3 2020 1.6 5.2 2021 1.4 4.4 2022 1.2 3.6 2023 1.1 3.4 2024 0.7 3.3 2025 and thereafter 1.4 18.9 Total minimum lease payments $ 7.8 $ 40.1 Less: interest (1.0 ) (10.6 ) Present value $ 6.8 $ 29.5 The following table presents minimum rental commitments at December 31, 2018 (in millions of dollars): Year Ended December 31, Finance Leases Operating Leases 2019 $ 1.7 $ 6.1 2020 1.4 3.7 2021 1.2 2.8 2022 1.1 2.4 2023 1.0 2.2 2024 and thereafter 1.8 20.8 Total minimum lease payments $ 8.2 $ 38.0 Less: interest (1.2 ) Present value 1 $ 7.0 _________________________ 1. Of the $7.0 million in finance lease obligations as of December 31, 2018, $1.4 million was included in Other accrued liabilities and $5.6 million was included in Long-term liabilities. Assets recorded under finance leases and the accumulated amortization thereon were $8.3 million and $1.3 million , respectively, as of December 31, 2018.

Employee Benefits

Employee Benefits	9 Months Ended
	Sep. 30, 2019
Retirement Benefits [Abstract]
Employee Benefits	Employee Benefits Pension and Similar Benefit Plans. We provide contributions to: (i) defined contribution 401(k) savings plans for salaried employees and certain hourly employees; (ii) a non-qualified, unfunded, unsecured plan of deferred compensation (see " Deferred Compensation Plan " below); (iii) multi-employer pension plans sponsored by the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union, AFL-CIO, CLC, the International Association of Machinists and certain other unions at certain of our production facilities; and (iv) a defined benefit pension plan for salaried employees at our London, Ontario (Canada) facility. Deferred Compensation Plan . We have a non-qualified, unfunded, unsecured plan of deferred compensation for certain employees who would otherwise suffer a loss of benefits under our defined contribution plan as a result of the limitations imposed by the Internal Revenue Code of 1986. Despite the plan being an unfunded plan, we make an annual contribution to a rabbi trust to fulfill future funding obligations as contemplated by the terms of the plan. The assets in the trust are held in various investment funds at certain registered investment companies and are accounted for as equity investments with changes in fair value recorded within Other (expense) income, net (see Note 9 ). Assets of our deferred compensation plan are included in Other assets, classified within Level 2 of the fair value hierarchy and are measured and recorded at fair value based on their quoted market prices. The fair value of these assets at September 30, 2019 and December 31, 2018 was $7.9 million and $10.5 million , respectively. Offsetting liabilities relating to the deferred compensation plan are included in Other accrued liabilities and Long-term liabilities. Salaried VEBA Postretirement Obligation. Certain retirees who retired prior to 2004 and certain employees who were hired prior to February 2002 and have subsequently retired or will retire with the requisite age and service, along with their surviving spouses and eligible dependents, are eligible to participate in a voluntary employees' beneficiary association ("VEBA") that provides healthcare cost, medical cost and long-term care insurance cost reimbursement benefits ("Salaried VEBA"). We have an ongoing obligation with no express termination date to make annual variable cash contributions up to a maximum of $2.9 million to the Salaried VEBA. We paid $2.1 million with respect to 2018 during the quarter ended March 31, 2019. We account for the Salaried VEBA as a defined benefit plan in our financial statements. Union VEBA Postretirement Obligation. Certain other eligible retirees represented by certain unions, along with their surviving spouses and eligible dependents, participate in a separate VEBA ("Union VEBA"). During the first quarter of 2018, we made a $12.8 million cash contribution to the Union VEBA with respect to the nine months ended September 30, 2017. This was our final contribution. We have no ongoing obligation to make further contributions to the Union VEBA. The following tables present the total expense related to all benefit plans for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Defined contribution plans 1 $ 1.7 $ 1.7 $ 7.3 $ 7.3 Deferred compensation plan 1 0.3 0.2 1.3 1.2 Multiemployer pension plans 1 1.3 1.2 3.7 3.5 Net periodic postretirement benefit cost relating to Salaried VEBA 2 1.6 1.4 4.9 4.5 Total $ 4.9 $ 4.5 $ 17.2 $ 16.5 ____________________ 1 Substantially all of the expense related to employee benefits are in COGS with the remaining balance in Selling, general, administrative, research and development ("SG&A and R&D"). 2 The current service cost component of Net periodic postretirement benefit cost relating to Salaried VEBA is included within our Statements of Consolidated Income in SG&A and R&D for all periods presented. All other components of Net periodic postretirement benefit cost relating to Salaried VEBA are included within Other (expense) income, net, on our Statements of Consolidated Income. Components of Net Periodic Benefit Cost. Our results of operations included the following impacts associated with our Canadian pension plan and the Salaried VEBA: (i) a charge for service rendered by employees; (ii) a charge for accretion of interest; (iii) a benefit for the expected return on plan assets; (iv) amortization of prior service costs associated with plan amendments; and (v) amortization of net actuarial differences. Net periodic benefit cost related to our Canadian pension plan was not material for the quarters and nine months ended September 30, 2019 and September 30, 2018 . The following table presents the components of Net periodic postretirement benefit cost relating to Salaried VEBA for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Salaried VEBA 1 : Interest cost $ 0.8 $ 0.7 $ 2.4 $ 2.1 Expected return on plan assets (0.7 ) (0.8 ) (2.0 ) (2.2 ) Amortization of prior service cost 2 1.4 1.3 4.2 4.0 Amortization of net actuarial loss 0.1 0.2 0.3 0.6 Total net periodic postretirement benefit cost relating to Salaried VEBA $ 1.6 $ 1.4 $ 4.9 $ 4.5 ____________________ 1 The service cost was insignificant for all periods presented. 2 We amortize prior service cost on a straight-line basis over the average remaining years of service to full eligibility for benefits of the active plan participants.

Derivatives, Hedging Programs a

Derivatives, Hedging Programs and Other Financial Instruments	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives, Hedging Programs and Other Financial Instruments	Derivatives, Hedging Programs and Other Financial Instruments Overview In conducting our business, we enter into derivative transactions, including forward contracts and options, to limit our exposure to: (i) metal price risk related to our sale of fabricated aluminum products and the purchase of metal used as raw material for our fabrication operations; (ii) energy price risk relating to fluctuating prices of natural gas and electricity used in our production processes; and (iii) foreign currency requirements with respect to cash commitments for equipment purchases denominated in foreign currency. Our derivative activities are overseen by a committee ("Hedging Committee"), which is composed of our chief executive officer, chief operating officer, chief financial officer, chief accounting officer, vice president of metal management, treasurer and other officers and employees selected by the chief executive officer. The Hedging Committee meets regularly to review commodity price exposure, derivative positions and strategy. Management reviews the scope of the Hedging Committee's activities with our Board of Directors. We are exposed to counterparty credit risk on all of our derivative instruments, which we manage by monitoring the credit quality of our counterparties and allocating our hedging positions among multiple counterparties to limit exposure to any single entity. Our counterparties are major, investment grade financial institutions or trading companies. Hedging transactions are governed by negotiated reciprocal credit lines, which generally require collateral to be posted above specified credit thresholds. We believe the risk of loss is remote and contained due to counterparty credit quality, our diversification practice and collateral requirements. In a majority of our hedging counterparty agreements, our counterparty offers us a credit line that adjusts up or down, depending on our liquidity. Below specified liquidity thresholds, we may have to post collateral if the fair value of our net liability with such counterparty exceeds our reduced credit line. We manage this risk by allocating hedging transactions among multiple counterparties, using options as part of our hedging activities or both. The aggregate fair value of our derivative instruments that were in a net liability position was $13.7 million and $12.6 million at September 30, 2019 and December 31, 2018 , respectively, and we had no collateral posted as of those dates. Additionally, our firm-price customer sales commitments create incremental customer credit risk related to metal price movements. Under certain circumstances, we mitigate this risk by periodically requiring cash collateral from them, which we classify as deferred revenue and include as a component of Other accrued liabilities. Cash collateral posted from our customers was $0.2 million at both September 30, 2019 and December 31, 2018 . For more information about concentration risks concerning customers and suppliers, see Note 13 . Aluminum Hedges . Our pricing of fabricated aluminum products is generally intended to lock in a conversion margin (representing the value added from the fabrication process(es)) and to pass through metal price fluctuations to our customers. For some of our higher value added products sold on a spot basis, the pass through of metal price movements can sometimes lag by as much as several months, with a favorable impact to us when metal prices decline and an adverse impact to us when metal prices increase. Additionally, in certain instances, we enter into firm-price arrangements with our customers for stipulated volumes to be delivered in the future. Because we generally purchase primary and secondary aluminum on a floating price basis, the lag in passing through metal price movements to customers on some of our higher value added products sold on a spot basis and the volume that we have committed to sell to our customers under a firm-price arrangement create metal price risk for us. We use third-party hedging instruments to limit exposure to metal price risk related to the metal pass through lag on some of our products and firm-price customer sales contracts. Alloying Metals Hedges . We are exposed to risk of fluctuating prices for Alloying Metals used as raw materials in our fabrication operations. We, from time to time, in the ordinary course of business, use third-party hedging instruments to mitigate our risk from price fluctuations in Alloying Metals. Energy Hedges . We are exposed to risk of fluctuating prices for natural gas and electricity. We, from time to time, in the ordinary course of business, enter into hedging transactions and/or physical delivery commitments with third parties to mitigate our risk from fluctuations in natural gas and electricity prices. Notional Amount of Derivative Contracts The following table summarizes our derivative positions at September 30, 2019 : Aluminum Maturity Period (month/year) Notional Amount of Contracts (mmlbs) Fixed price purchase contracts 10/19 through 12/21 83.1 Fixed price sales contracts 11/19 through 9/21 0.8 Midwest premium swap contracts 1 10/19 through 12/21 57.6 Alloying Metals Maturity Period (month/year) Notional Amount of Contracts (mmlbs) Fixed price purchase contracts 10/19 through 12/21 12.9 Natural Gas 2 Maturity Period (month/year) Notional Amount of Contracts (mmbtu) Fixed price purchase contracts 10/19 through 12/24 7,930,000 Electricity 3 Maturity Period (month/year) Notional Amount of Contracts (Mwh) Fixed price purchase contracts 1/20 through 12/21 394,680 Euro 4 Maturity Period (month/year) Notional Amount of Contracts (euro) Fixed price purchase contracts 10/19 through 1/20 3,189,200 ____________________ 1 Regional premiums represent the premium over the London Metal Exchange price for primary aluminum which is incurred on our purchases of primary aluminum. 2 As of September 30, 2019 , we had derivative and/or physical delivery commitments with energy companies in place to cover exposure to fluctuations in prices for approximately 72% of the expected natural gas purchases for the remainder of 2019 , 68% of the expected natural gas purchases for both 2020 and 2021 , 83% of the expected natural gas purchases for both 2022 and 2023 and 77% of the expected natural gas purchases for 2024. 3 As of September 30, 2019 , we had derivative and/or physical delivery commitments with energy companies in place to cover exposure to fluctuations in prices for approximately 54% of our expected electricity purchases for the remainder of 2019 , 55% of our expected electricity purchases for 2020 and 46% of our expected electricity purchases for 2021 . 4 We are exposed to foreign currency exchange risk related to firm-price agreements for equipment purchases from foreign manufacturers. We use non-designated foreign currency forward contracts designed to line up with the timing and amounts of scheduled payments to the foreign equipment manufacturers to mitigate our exposure to currency exchange rate fluctuations on these purchases. Loss (Gain) See Note 8 for the total amount of loss (gain) for the quarters and nine months ended September 30, 2019 and September 30, 2018 on derivative instruments designated and qualifying as cash flow hedging instruments that was reported in Accumulated other comprehensive loss ("AOCI"), as well as the related reclassifications into earnings and tax effects. Cumulative gains and losses related to cash flow hedges are reclassified out of AOCI when the associated hedged commodity purchases impact earnings. The amount of loss (gain) included on our Statements of Consolidated Income (all within COGS) associated with all derivative contracts consisted of the following for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended 2019 2018 2019 2018 Total amounts of income and expense line items presented in our Statements of Consolidated Income in which the effects of hedges are recorded $ 298.6 $ 323.3 $ 917.2 $ 983.4 Loss (gain) recognized in income related to cash flow hedges: Aluminum $ 4.8 $ 2.1 $ 13.5 $ (1.2 ) Alloying metals 0.5 1.0 0.7 0.4 Natural gas 0.1 — 0.1 (0.1 ) Total loss (gain) recognized in income related to cash flow hedges $ 5.4 $ 3.1 $ 14.3 $ (0.9 ) Loss recognized in income related to non-designated hedges: Foreign currency $ 0.1 $ — $ 0.1 $ — Total loss recognized in income related to non-designated hedges $ 0.1 $ — $ 0.1 $ — Fair Values of Derivative Contracts The fair values of our derivative contracts are based upon trades in liquid markets. Valuation model inputs can be verified and valuation techniques do not involve significant judgment. The fair values of such financial instruments are classified within Level 2 of the fair value hierarchy. All of our derivative contracts with counterparties are subject to enforceable master netting arrangements. We reflect the fair value of our derivative contracts on a gross basis on our Consolidated Balance Sheets. The following table presents the fair value of our derivative financial instruments as of the periods presented (in millions of dollars): September 30, 2019 December 31, 2018 Derivative Assets Derivative Liabilities Net Amount Derivative Assets Derivative Liabilities Net Amount Cash Flow Hedges: Aluminum – Fixed price purchase contracts $ — $ (10.2 ) $ (10.2 ) $ 0.1 $ (13.2 ) $ (13.1 ) Fixed price sales contracts 0.1 — 0.1 0.1 — 0.1 Midwest premium swap contracts 0.6 (0.1 ) 0.5 3.2 (0.5 ) 2.7 Alloying Metals – Fixed price purchase contracts — (2.0 ) (2.0 ) — (1.7 ) (1.7 ) Natural gas – Fixed price purchase contracts — (2.0 ) (2.0 ) 0.2 (0.5 ) (0.3 ) Electricity – Fixed price purchase contracts 1.5 (1.5 ) — 0.7 — 0.7 Non-Designated Hedges: Foreign currency – Fixed price purchase contracts — (0.1 ) (0.1 ) — — — Total $ 2.2 $ (15.9 ) $ (13.7 ) $ 4.3 $ (15.9 ) $ (11.6 ) The following table presents the total amounts of derivative assets and liabilities on our Consolidated Balance Sheets as of the periods presented (in millions of dollars): September 30, 2019 December 31, 2018 Derivative assets: Prepaid expenses and other current assets $ 1.2 $ 3.4 Other assets 1.0 0.9 Total derivative assets $ 2.2 $ 4.3 Derivative liabilities: Other accrued liabilities $ (12.8 ) $ (13.2 ) Long-term liabilities (3.1 ) (2.7 ) Total derivative liabilities $ (15.9 ) $ (15.9 ) Fair Value of Other Financial Instruments Cash and Cash Equivalents. See Note 2 for components of cash and cash equivalents. Available for Sale Securities. We hold debt investment securities that are accounted for as available for sale securities and are presented as cash equivalents and short-term investments on our Consolidated Balance Sheets. The fair value of the debt investment securities, which consist of commercial paper, is determined based on valuation models that use observable market data. At September 30, 2019 , all of our short-term investments had maturity dates within 12 months . We review our debt investment portfolio for other-than-temporary impairment at least quarterly or when there are changes in credit risk or other potential valuation concerns. At September 30, 2019 and December 31, 2018 , the total unrealized loss, net of tax, included in AOCI was immaterial and was not other-than-temporarily impaired. We believe that it is probable that the principal and interest will be collected in accordance with the contractual terms, and that the unrealized loss on these securities was due to normal market fluctuations, and not due to increased credit risk or other valuation concerns. The fair value input of our available for sale securities, which are classified within Level 2 of the fair value hierarchy, is calculated based on broker quotes. The amortized cost for available for sale securities approximates their fair value. The following table classifies our other financial assets under the appropriate level of the fair value hierarchy as of September 30, 2019 (in millions of dollars): Level 1 Level 2 Level 3 Total Cash and cash equivalents 29.3 142.8 $ — $ 172.1 Short-term investments — 25.3 — 25.3 Total $ 29.3 $ 168.1 $ — $ 197.4 The following table classifies our other financial assets under the appropriate level of the fair value hierarchy as of December 31, 2018 (in millions of dollars): Level 1 Level 2 Level 3 Total Cash and cash equivalents 22.9 102.7 $ — $ 125.6 Short-term investments — 36.7 — 36.7 Total $ 22.9 $ 139.4 $ — $ 162.3 All Other Financial Assets and Liabilities.

Debt and Credit Facility

Debt and Credit Facility	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Debt and Credit Facility	Debt and Credit Facility Senior Notes In May 2016, we issued $375.0 million principal amount of 5.875% unsecured senior notes due May 15, 2024 ("Senior Notes") at 100% of the principal amount. The unamortized amount of debt issuance costs as of September 30, 2019 was $3.9 million . Interest expense, including amortization of debt issuance costs, relating to the Senior Notes was $5.7 million for each of the quarters ended September 30, 2019 and September 30, 2018 . Interest expense, including amortization of debt issuance costs, relating to the Senior Notes was $17.1 million for each of the nine months ended September 30, 2019 and September 30, 2018 . A portion of the interest relating to the Senior Notes was capitalized as construction in progress. The effective interest rate of the Senior Notes is approximately 6.1% per annum, taking into account the amortization of debt issuance costs. The fair value of the outstanding Senior Notes, which are Level 1 liabilities, was approximately $386.8 million and $369.9 million at September 30, 2019 and December 31, 2018 , respectively. Revolving Credit Facility Our credit agreement with JPMorgan Chase Bank, N.A., as administrative agent, and the other financial institutions party thereto ("Revolving Credit Facility") provides us with a $300.0 million funding commitment through December 2020. We had $300.0 million of borrowing availability under the Revolving Credit Facility at September 30, 2019 , based on the borrowing base determination then in effect. At September 30, 2019 , there were no borrowings under the Revolving Credit Facility and $8.0 million was being used to support outstanding letters of credit, leaving $292.0 million of net borrowing availability. The interest rate applicable to any overnight borrowings under the Revolving Credit Facility would have been 5.25% at September 30, 2019 .

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments. We have a variety of financial commitments, including purchase agreements, forward foreign exchange and forward sales contracts, indebtedness and letters of credit (see Note 5 and Note 6 ). Environmental Contingencies. We are subject to a number of environmental laws and regulations, to potential fines or penalties assessed for alleged breaches of such laws and regulations and to potential claims based upon such laws and regulations. We are also subject to legacy environmental contingencies related to activities that occurred at operating facilities prior to July 6, 2006, which represent the majority of our environmental accruals. The status of these environmental contingencies are discussed below. We have established procedures for regularly evaluating environmental loss contingencies. Our environmental accruals represent our undiscounted estimate of costs reasonably expected to be incurred based on presently enacted laws and regulations, existing requirements, currently available facts, existing technology and our assessment of the likely remediation actions to be taken. We continue to pursue remediation activities, primarily to address the historical use of oils containing polychlorinated biphenyls ("PCBs") at our Spokane, Washington ("Trentwood") facility. Our remediation efforts are in collaboration with the Washington State Department of Ecology ("Washington State Ecology"), to which we submitted a feasibility study in 2012 of remediation alternatives and from which we received permission to begin certain remediation activities pursuant to a signed work order. As we have finished a number of sections of the work plan, we have received approval from Washington State Ecology on satisfactory completion of those sections. Additionally, in cooperation with Washington State Ecology, to determine the treatability and evaluate the feasibility of removing PCBs from ground water under the Trentwood facility, we constructed an experimental treatment facility and began treatment operations in 2016. As the long-term success of the new methodology cannot be reasonably determined at this time, it is possible we may need to make upward adjustments to our related accruals and cost estimates as the long-term results become available. During 2013, at the request of the Ohio Environmental Protection Agency ("OEPA"), we initiated an investigational study of the Newark, Ohio ("Newark") facility related to historical on-site waste disposal. In the fourth quarter of 2018, we submitted our remedial investigation study to the OEPA, which is subject to their review and approval. Following OEPA approval of the remedial investigational study, we will then prepare the final feasibility study and update estimates for probable and estimable remediation, if any. The actual and final cost for remediation will not be fully determinable until a final feasibility study is submitted and accepted by the OEPA and work plans are prepared, which is expected to occur in the next six to 12 months . At September 30, 2019 , our environmental accrual of $16.5 million represented our estimate of the incremental remediation cost based on: (i) proposed alternatives in the final feasibility study related to the Trentwood facility; (ii) currently available facts with respect to our Newark facility; and (iii) facts related to certain other locations owned or formerly owned by us. In accordance with approved and proposed remediation action plans, we expect that the implementation and ongoing monitoring could occur over a period of 30 or more years. As additional facts are developed, feasibility studies are completed, remediation plans are modified, necessary regulatory approvals for the implementation of remediation are obtained, alternative technologies are developed and/or other factors change, there may be revisions to management's estimates and actual costs may exceed the current environmental accruals. We believe at this time that it is reasonably possible that undiscounted costs associated with these environmental matters may exceed current accruals by amounts that could be, in the aggregate, up to an estimated $11.6 million over the remediation period. It is reasonably possible that our recorded estimate will change in the next 12 months . Other Contingencies. We are party to various lawsuits, claims, investigations and administrative proceedings that arise in connection with past and current operations. We evaluate such matters on a case-by-case basis and our policy is to vigorously contest any such claims we believe are without merit. We accrue for a legal liability when it is both probable that a liability has been incurred and the amount of the loss is reasonably estimable. Quarterly, in addition to when changes in facts and circumstances require it, we review and adjust these accruals to reflect the impacts of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular case. While uncertainties are inherent in the final outcome of such matters and it is presently impossible to determine the actual cost that may ultimately be incurred, we believe that we have sufficiently accrued for such matters and that the ultimate resolution of pending matters will not have a material impact on our consolidated financial position, operating results or liquidity.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss The following table presents the changes in the accumulated balances for each component of AOCI for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Defined Benefit Pension Plan and Salaried VEBA: Beginning balance $ (33.4 ) $ (36.1 ) $ (35.6 ) $ (38.5 ) Amortization of net actuarial loss 1 0.1 0.2 0.3 0.6 Amortization of prior service cost 1 1.4 1.3 4.2 4.0 Less: income tax expense 2 (0.3 ) (0.4 ) (1.1 ) (1.1 ) Net amortization reclassified from AOCI to Net income 1.2 1.1 3.4 3.5 Other comprehensive income, net of tax 1.2 1.1 3.4 3.5 Ending balance $ (32.2 ) $ (35.0 ) $ (32.2 ) $ (35.0 ) Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Available for Sale Securities: Beginning balance $ — $ 0.6 $ 0.3 $ 0.9 Unrealized gain on available for sale securities 1.0 1.3 2.7 3.6 Less: income tax expense (0.3 ) (0.3 ) (0.7 ) (0.9 ) Net unrealized gain on available for sale securities 0.7 1.0 2.0 2.7 Reclassification of unrealized gain upon sale of available for sale securities 3 (0.9 ) (1.6 ) (3.0 ) (4.3 ) Less: income tax benefit 2 0.3 0.4 0.8 1.1 Net gain reclassified from AOCI to Net income (0.6 ) (1.2 ) (2.2 ) (3.2 ) Other comprehensive income (loss), net of tax 0.1 (0.2 ) (0.2 ) (0.5 ) Ending balance $ 0.1 $ 0.4 $ 0.1 $ 0.4 Cash Flow Hedges: Beginning balance $ (8.8 ) $ (3.5 ) $ (13.4 ) $ 0.5 Unrealized loss on cash flow hedges (8.4 ) (5.2 ) (11.1 ) (6.5 ) Less: income tax benefit 2.1 1.2 2.7 1.6 Net unrealized loss on cash flow hedges (6.3 ) (4.0 ) (8.4 ) (4.9 ) Reclassification of unrealized loss (gain) upon settlement of cash flow hedges 4 5.4 3.0 14.3 (1.0 ) Less: income tax (expense) benefit 2 (1.3 ) (0.7 ) (3.5 ) 0.2 Net loss (gain) reclassified from AOCI to Net income 4.1 2.3 10.8 (0.8 ) Other comprehensive (loss) income, net of tax (2.2 ) (1.7 ) 2.4 (5.7 ) Ending balance $ (11.0 ) $ (5.2 ) $ (11.0 ) $ (5.2 ) Foreign Currency Translation: Beginning balance $ (0.1 ) $ — $ (0.1 ) $ — Other comprehensive income, net of tax — — — — Ending balance $ (0.1 ) $ — $ (0.1 ) $ — Total AOCI ending balance $ (43.2 ) $ (39.8 ) $ (43.2 ) $ (39.8 ) ____________________ 1 Amounts amortized out of AOCI relating to Salaried VEBA adjustments were included within Other (expense) income, net, as a component of Net periodic postretirement benefit cost relating to Salaried VEBA. 2 Income tax amounts reclassified out of AOCI were included as a component of Income tax provision. 3 Amounts reclassified out of AOCI relating to sales of available for sale securities were included as a component of Other (expense) income, net. We use the specific identification method to determine the amount reclassified out of AOCI. 4 Amounts reclassified out of AOCI relating to cash flow hedges were included as a component of COGS. As of September 30, 2019 , we estimate a net mark-to-market loss before tax of $12.2 million in AOCI will be reclassified into Net income within the next 12 months.

Other (Expense) Income, Net

Other (Expense) Income, Net	9 Months Ended
	Sep. 30, 2019
Other Income and Expenses [Abstract]
Other (Expense) Income, Net	Other (Expense) Income, Net Other (expense) income, net, consisted of the following for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Interest income $ 0.2 $ 0.1 $ 0.5 $ 0.2 Net periodic postretirement benefit cost relating to Salaried VEBA (1.6 ) (1.4 ) (4.9 ) (4.5 ) Realized gain on available for sale securities 0.9 1.6 3.0 4.3 Unrealized gain (loss) on equity securities 0.1 0.1 0.6 (0.3 ) All other (expense) income, net (0.4 ) 0.3 0.4 0.6 Other (expense) income, net $ (0.8 ) $ 0.7 $ (0.4 ) $ 0.3

Income Tax Matters

Income Tax Matters	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Tax Matters	Income Tax Matters The provision for in come taxes consisted of the following for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Domestic $ 8.5 $ 7.5 $ 24.7 $ 20.5 Foreign 0.2 0.7 1.1 1.4 Total $ 8.7 $ 8.2 $ 25.8 $ 21.9 The income tax provision for the quarters ended September 30, 2019 and September 30, 2018 was $8.7 million and $8.2 million , respectively, reflecting an effective tax rate of 26% and 27% , respectively. The difference between the effective tax rate and the projected blended statutory tax rate for the quarter ended September 30, 2019 was primarily due to an increase of $0.5 million ( 2% of taxable income) related to non-deductible compensation expense. The difference between the effective tax rate and the projected blended statutory tax rate for the quarter ended September 30, 2018 was primarily due to: (i) an increase of $0.6 million ( 2% of taxable income) related to non-deductible compensation expense; (ii) an increase of $0.3 million ( 1% of taxable income) for an Advance Pricing Agreement settlement with Canada; and (iii) an increase of $0.2 million ( 1% of taxable income) for the sequestration of AMT credits, partially offset by a decrease of $0.4 million ( 1% of taxable income) to the valuation allowance for certain state net operating losses. The income tax provision for the nine months ended September 30, 2019 and September 30, 2018 was $25.8 million and $21.9 million , respectively, reflecting an effective tax rate of 26% and 24% respectively. The difference between the effective tax rate and the projected blended statutory tax rate for the nine months ended September 30, 2019 was primarily due to: (i) an increase of $1.5 million ( 2% of taxable income) related to non-deductible compensation expense; (ii) an increase of $0.6 million ( 1% of taxable income) to the valuation allowance for certain state net operating losses, partially offset by a decrease of $0.6 million ( 1% of taxable income) for the recognition of excess tax benefits from stock-based compensation. The difference between the effective tax rate and the projected blended statutory tax rate for the nine months ended September 30, 2018 was due to: (i) a decrease of $2.0 million ( 2% of taxable income) for the recognition of excess tax benefits from stock-based compensation and (ii) a decrease of $0.9 million ( 1% of taxable income) to the valuation allowance for certain state net operating losses, partially offset by: (i) an increase of $1.7 million ( 2% of taxable income) related to non-deductible compensation expense and (ii) an increase of $0.6 million ( 1% of taxable income) for the sequestration of AMT credits. Our gross unrecognized benefits relating to uncertain tax positions were $1.7 million and $1.5 million at September 30, 2019 and December 31, 2018 , respectively, of which, $0.6 million and $0.4 million would be recorded through our income tax provision and thus impact the effective tax rate at September 30, 2019 and December 31, 2018 , respectively, if the gross unrecognized tax benefits were to be recognized. We do not expect our gross unrecognized tax benefits to significantly change within the next 12 months .

Net Income Per Share and Stockh

Net Income Per Share and Stockholders' Equity	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Net Income per Share and Stockholders Equity	Net Income Per Share and Stockholders' Equity Net Income Per Share . Basic net income per share is computed by dividing distributed and undistributed net income allocable to common shares by the weighted-average number of common shares outstanding during the applicable period. The basic weighted-average number of common shares outstanding during the period excludes non-vested share-based payment awards. Diluted net income per share was calculated under the treasury stock method for the quarters and nine months ended September 30, 2019 and September 30, 2018 , which in all periods was more dilutive than the two-class method. The following table sets forth the computation of basic and diluted net income per share for the periods presented (in millions of dollars, except share and per share amounts): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Numerator: Net income $ 25.4 $ 21.7 $ 72.6 $ 68.1 Denominator – Weighted-average common shares outstanding (in thousands): Basic 15,956 16,573 16,042 16,654 Add: dilutive effect of non-vested common shares, restricted stock units and performance shares 1 169 210 193 228 Diluted 16,125 16,783 16,235 16,882 Net income per common share, Basic: $ 1.59 $ 1.31 $ 4.52 $ 4.09 Net income per common share, Diluted: $ 1.57 $ 1.29 $ 4.47 $ 4.03 ____________________ 1 During both the quarter and nine months ended September 30, 2019 , a total of seven thousand securities were excluded from the weighted-average diluted shares computation as their inclusion would have been anti-dilutive. There were no anti-dilutive securities during both the quarter and nine months ended September 30, 2018 . Preferred Stock . In connection with a tax asset protection rights plan, our Board of Directors declared a dividend, payable April 22, 2016, of one

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Nine Months Ended September 30, 2019 2018 (In millions of dollars) Interest paid $ 10.6 $ 10.6 Non-cash investing and financing activities (included in Accounts payable): Unpaid purchases of property and equipment $ 3.3 $ 5.8 Stock repurchases not yet settled $ 0.3 $ 0.4 Supplemental lease disclosures: Operating lease liabilities arising from obtaining operating lease assets $ 1.6 n/a Cash paid for amounts included in the measurement of operating lease liabilities $ 2.8 n/a Finance lease liabilities arising from obtaining finance lease assets $ 0.9 $ 0.3 September 30, 2019 September 30, 2018 (In millions of dollars) Components of cash, cash equivalents and restricted cash: Cash and cash equivalents $ 172.1 $ 94.3 Restricted cash included in Prepaid expenses and other current assets 1 0.3 0.3 Restricted cash included in Other assets 1 14.1 14.5 Total cash, cash equivalents and restricted cash presented on our Statements of Consolidated Cash Flows $ 186.5 $ 109.1 ____________________ 1

Business, Product and Geographi

Business, Product and Geographical Area Information and Concentration of Risk	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Business, Product and Geographical Area Information and Concentration of Risk	Business, Product and Geographical Area Information and Concentration of Risk Our primary line of business is the production of semi-fabricated specialty aluminum mill products, such as aluminum plate and sheet and extruded and drawn products, primarily used in Aero/HS products, Automotive Extrusions, GE products and Other products. We operate 12 focused production facilities in the United States and one in Canada. Our chief operating decision maker reviews and evaluates our business as a single operating segment. At September 30, 2019 , approximately 62% of our employees were covered by collective bargaining agreements and approximately 35% of our employees were covered by collective bargaining agreements with expiration dates occurring within one year from September 30, 2019 . Net sales by end market applications and by timing of control transfer for the periods presented were as follows (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Net sales: Aero/HS products $ 198.9 $ 185.7 $ 586.8 $ 540.9 Automotive Extrusions 47.5 56.1 146.0 183.9 GE products 117.1 133.9 375.3 425.1 Other products 11.4 17.4 37.3 46.6 Total net sales $ 374.9 $ 393.1 $ 1,145.4 $ 1,196.5 Timing of revenue recognition: Products transferred at a point in time $ 115.9 $ 127.8 $ 378.7 $ 425.2 Products transferred over time 259.0 265.3 766.7 771.3 Total net sales $ 374.9 $ 393.1 $ 1,145.4 $ 1,196.5 Geographic information for income taxes paid for the periods presented was as follows (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Income taxes paid: Domestic $ 0.1 $ 0.4 $ 2.0 $ 1.3 Foreign 0.4 — 1.6 2.0 Total income taxes paid $ 0.5 $ 0.4 $ 3.6 $ 3.3 Concentrations . For the quarter ended September 30, 2019 , one customer represented 24% and another represented 19% of Net sales. For the quarter ended September 30, 2018 , one customer represented 26% and another represented 15% of Net sales. For the nine months ended September 30, 2019 , one customer represented 25% and another represented 16% of Net sales. For the nine months ended September 30, 2018 , one customer represented 26% and another represented 13% of Net sales. At September 30, 2019 , one individual customer accounted for 33% and another individual customer accounted for 12% of the accounts receivable balance. One individual customer accounted for 31% and another individual customer accounted for 11% of the accounts receivable balance at December 31, 2018 . Information about primary aluminum supply from our major suppliers for the periods presented was as follows: Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Percentage of total primary aluminum supply (lbs): Supply from our top five major suppliers 81 % 83 % 74 % 82 % Supply from our largest supplier 23 % 33 % 21 % 36 % Supply from our second and third largest suppliers combined 38 % 36 % 33 % 32 %

Condensed Guarantor and Non-Gua

Condensed Guarantor and Non-Guarantor Financial Information	9 Months Ended
	Sep. 30, 2019
Guarantor and Non-Guarantor Financial Statement [Abstract]
Condensed Guarantor and Non-Guarantor Financial Statements	Condensed Guarantor and Non-Guarantor Financial Information During the quarter ended June 30, 2016, we issued $375.0 million aggregate principal amount of our Senior Notes. The Senior Notes were issued by Kaiser Aluminum Corporation ("Parent") pursuant to an indenture dated May 12, 2016 ("Indenture") with Wells Fargo Bank, National Association, as trustee. The obligations of the Parent under the Indenture are guaranteed by Kaiser Aluminum Investments Company, Kaiser Aluminum Fabricated Products, LLC and Kaiser Aluminum Washington, LLC ("Guarantor Subsidiaries"). All Guarantor Subsidiaries are 100% owned by Parent. The guarantees are full and unconditional and joint and several but have customary releases in the following situations: (i) the sale of the Guarantor Subsidiary or all of its assets; (ii) the declaration of a Guarantor Subsidiary as an unrestricted subsidiary under the Indenture; (iii) the termination or release of the Guarantor Subsidiary's guarantee of certain other indebtedness; or (iv) our exercise of legal defeasance or covenant defeasance or the discharge of our obligations under the Indenture. The following condensed consolidating financial information as of September 30, 2019 and December 31, 2018 and for the quarters and nine months ended September 30, 2019 and September 30, 2018 present: (i) the financial position, results of operations and cash flows for each of (a) Parent, (b) the Guarantor Subsidiaries on a combined basis and (c) the Non-Guarantor subsidiaries of Parent other than the Guarantor Subsidiaries ("Non-Guarantor Subsidiaries") on a combined basis; (ii) the "Consolidating Adjustments," which represent the adjustments necessary to eliminate the investments in our subsidiaries, other intercompany balances and other intercompany sales and cost of sales among Parent, the Guarantor Subsidiaries and the Non-Guarantor Subsidiaries; and (iii) the resulting totals, reflecting information for us on a consolidated basis, as reported. The condensed consolidating financial information should be read in conjunction with our consolidated financial statements herein. The Non-Guarantor Subsidiaries include Kaiser Aluminum Mill Products, Inc., Kaiser Aluminum Canada Limited, Trochus Insurance Company, Kaiser Aluminum France, S.A.S., Kaiser Aluminum Beijing Trading Company, Imperial Machine & Tool, Co. and Solid Innovations, LLC. CONDENSED CONSOLIDATING BALANCE SHEET (In millions of dollars) September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated ASSETS Current assets: Cash and cash equivalents $ — $ 170.7 $ 1.4 $ — $ 172.1 Short-term investments — 25.3 — — 25.3 Receivables: Trade receivables, net — 183.2 4.9 — 188.1 Intercompany loans receivable 50.6 1.4 5.5 (57.5 ) — Other — 24.3 1.8 — 26.1 Contract assets — 43.6 2.5 — 46.1 Inventories — 183.1 9.4 — 192.5 Prepaid expenses and other current assets 0.3 17.7 0.4 — 18.4 Total current assets 50.9 649.3 25.9 (57.5 ) 668.6 Investments in and advances to subsidiaries 1,081.4 95.7 0.2 (1,177.3 ) — Property, plant and equipment, net — 580.6 33.7 — 614.3 Operating lease assets — 26.3 — — 26.3 Long-term intercompany loans receivable — — 17.0 (17.0 ) — Deferred tax assets, net — 3.3 — 3.0 6.3 Intangible assets, net — 22.6 7.7 — 30.3 Goodwill — 18.7 25.3 — 44.0 Other assets — 36.2 0.2 0.1 36.5 Total $ 1,132.3 $ 1,432.7 $ 110.0 $ (1,248.7 ) $ 1,426.3 LIABILITIES AND STOCKHOLDERS ' EQUITY Current liabilities: Accounts payable $ 1.5 $ 86.7 $ 5.6 $ — $ 93.8 Intercompany loans payable — 56.1 1.4 (57.5 ) — Accrued salaries, wages and related expenses — 30.3 1.6 — 31.9 Other accrued liabilities 8.3 46.1 0.5 (4.8 ) 50.1 Total current liabilities 9.8 219.2 9.1 (62.3 ) 175.8 Long-term portion of operating lease liabilities — 25.6 — — 25.6 Net liabilities of Salaried VEBA — 32.8 — — 32.8 Deferred tax liabilities — — 4.2 — 4.2 Long-term intercompany loans payable — 17.0 — (17.0 ) — Long-term liabilities — 61.8 3.6 — 65.4 Long-term debt 371.1 — — — 371.1 Total liabilities 380.9 356.4 16.9 (79.3 ) 674.9 Total stockholders' equity 751.4 1,076.3 93.1 (1,169.4 ) 751.4 Total $ 1,132.3 $ 1,432.7 $ 110.0 $ (1,248.7 ) $ 1,426.3 CONDENSED CONSOLIDATING BALANCE SHEET (In millions of dollars) December 31, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated ASSETS Current assets: Cash and cash equivalents $ — $ 122.6 $ 3.0 $ — $ 125.6 Short-term investments — 36.7 — — 36.7 Receivables: Trade receivables, net — 174.0 5.8 — 179.8 Intercompany receivables 143.7 0.1 4.3 (148.1 ) — Other — 23.3 2.3 — 25.6 Contract assets — 52.0 2.9 — 54.9 Inventories — 203.0 12.1 — 215.1 Prepaid expenses and other current assets 0.1 18.4 0.4 — 18.9 Total current assets 143.8 630.1 30.8 (148.1 ) 656.6 Investments in and advances to subsidiaries 974.7 94.9 0.2 (1,069.8 ) — Property, plant and equipment, net — 577.4 34.4 — 611.8 Long-term intercompany receivables — — 9.8 (9.8 ) — Deferred tax assets, net — 32.9 — 3.0 35.9 Intangible assets, net — 23.6 8.8 — 32.4 Goodwill — 18.8 25.2 — 44.0 Other assets — 38.6 — — 38.6 Total $ 1,118.5 $ 1,416.3 $ 109.2 $ (1,224.7 ) $ 1,419.3 LIABILITIES AND STOCKHOLDERS ' EQUITY Current liabilities: Accounts payable $ 4.9 $ 109.6 $ 6.9 $ — $ 121.4 Intercompany payable — 148.0 0.1 (148.1 ) — Accrued salaries, wages and related expenses — 38.3 1.8 — 40.1 Other accrued liabilities 2.8 46.7 0.8 (6.3 ) 44.0 Total current liabilities 7.7 342.6 9.6 (154.4 ) 205.5 Net liabilities of Salaried VEBA — 32.4 — — 32.4 Deferred tax liabilities — — 4.2 — 4.2 Long-term intercompany payable — 9.8 — (9.8 ) — Long-term liabilities — 63.3 3.1 — 66.4 Long-term debt 370.4 — — — 370.4 Total liabilities 378.1 448.1 16.9 (164.2 ) 678.9 Total stockholders' equity 740.4 968.2 92.3 (1,060.5 ) 740.4 Total $ 1,118.5 $ 1,416.3 $ 109.2 $ (1,224.7 ) $ 1,419.3 CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (In millions of dollars) Quarter Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Net sales $ — $ 365.2 $ 25.6 $ (15.9 ) $ 374.9 Costs and expenses: Cost of products sold, excluding depreciation and amortization and other items — 293.4 20.7 (15.5 ) 298.6 Depreciation and amortization — 11.3 1.0 — 12.3 Selling, general, administrative, research and development 1.5 19.6 2.6 (0.4 ) 23.3 Total costs and expenses 1.5 324.3 24.3 (15.9 ) 334.2 Operating (loss) income (1.5 ) 40.9 1.3 — 40.7 Other (expense) income: Interest expense (5.3 ) (0.6 ) — 0.1 (5.8 ) Other (expense) income, net — (0.8 ) 0.1 (0.1 ) (0.8 ) (Loss) income before income taxes (6.8 ) 39.5 1.4 — 34.1 Income tax provision — (10.0 ) (0.4 ) 1.7 (8.7 ) Earnings in equity of subsidiaries 32.2 1.0 — (33.2 ) — Net income $ 25.4 $ 30.5 $ 1.0 $ (31.5 ) $ 25.4 Comprehensive income $ 24.5 $ 29.6 $ 1.0 $ (30.6 ) $ 24.5 CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (In millions of dollars) Quarter Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Net sales $ — $ 385.9 $ 33.7 $ (26.5 ) $ 393.1 Costs and expenses: Cost of products sold, excluding depreciation and amortization and other items — 317.9 31.5 (26.1 ) 323.3 Depreciation and amortization — 10.5 0.5 — 11.0 Selling, general, administrative, research and development 1.0 22.8 0.5 (0.4 ) 23.9 Total costs and expenses 1.0 351.2 32.5 (26.5 ) 358.2 Operating (loss) income (1.0 ) 34.7 1.2 — 34.9 Other (expense) income: Interest expense (5.4 ) (0.4 ) — 0.1 (5.7 ) Other income, net — 0.6 0.2 (0.1 ) 0.7 (Loss) income before income taxes (6.4 ) 34.9 1.4 — 29.9 Income tax provision — (9.0 ) (0.8 ) 1.6 (8.2 ) Earnings in equity of subsidiaries 28.1 0.6 — (28.7 ) — Net income $ 21.7 $ 26.5 $ 0.6 $ (27.1 ) $ 21.7 Comprehensive income $ 20.9 $ 25.7 $ 0.6 $ (26.3 ) $ 20.9 CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (In millions of dollars) Nine Months Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Net sales $ — $ 1,117.8 $ 78.2 $ (50.6 ) $ 1,145.4 Costs and expenses: Cost of products sold, excluding depreciation and amortization and other items — 898.4 68.2 (49.4 ) 917.2 Depreciation and amortization — 33.3 3.0 — 36.3 Selling, general, administrative, research and development 4.0 67.4 5.5 (1.2 ) 75.7 Other operating charges, net — 0.1 — — 0.1 Total costs and expenses 4.0 999.2 76.7 (50.6 ) 1,029.3 Operating (loss) income (4.0 ) 118.6 1.5 — 116.1 Other (expense) income: Interest expense (15.9 ) (1.7 ) — 0.3 (17.3 ) Other (expense) income, net — (0.6 ) 0.5 (0.3 ) (0.4 ) (Loss) income before income taxes (19.9 ) 116.3 2.0 — 98.4 Income tax provision — (30.0 ) (0.7 ) 4.9 (25.8 ) Earnings in equity of subsidiaries 92.5 1.3 — (93.8 ) — Net income $ 72.6 $ 87.6 $ 1.3 $ (88.9 ) $ 72.6 Comprehensive income $ 78.2 $ 93.2 $ 1.3 $ (94.5 ) $ 78.2 CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (In millions of dollars) Nine Months Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Net sales $ — $ 1,168.5 $ 103.3 $ (75.3 ) $ 1,196.5 Costs and expenses: Cost of products sold, excluding depreciation and amortization and other items — 962.9 93.5 (73.0 ) 983.4 Depreciation and amortization — 30.8 1.6 — 32.4 Selling, general, administrative, research and development 3.7 67.8 4.7 (2.3 ) 73.9 Other operating charges, net — 0.1 — — 0.1 Total costs and expenses 3.7 1,061.6 99.8 (75.3 ) 1,089.8 Operating (loss) income (3.7 ) 106.9 3.5 — 106.7 Other (expense) income: Interest expense (15.9 ) (1.5 ) — 0.4 (17.0 ) Other income, net — 0.4 0.3 (0.4 ) 0.3 (Loss) income before income taxes (19.6 ) 105.8 3.8 — 90.0 Income tax provision — (25.3 ) (1.4 ) 4.8 (21.9 ) Earnings in equity of subsidiaries 87.7 2.4 — (90.1 ) — Net income $ 68.1 $ 82.9 $ 2.4 $ (85.3 ) $ 68.1 Comprehensive income $ 65.4 $ 80.2 $ 2.4 $ (82.6 ) $ 65.4 CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS (In millions of dollars) Nine Months Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ (16.5 ) $ 163.6 $ 7.3 $ (0.5 ) $ 153.9 Cash flows from investing activities: Capital expenditures — (39.4 ) (1.3 ) — (40.7 ) Purchase of available for sale securities — (56.3 ) — — (56.3 ) Purchase of equity securities — (0.7 ) — — (0.7 ) Proceeds from disposition of available for sale securities — 68.2 — — 68.2 Proceeds from disposal of property, plant and equipment — 0.2 — — 0.2 Intercompany loans receivable 93.1 (1.3 ) (8.4 ) (83.4 ) — Net cash provided by (used in) investing activities 93.1 (29.3 ) (9.7 ) (83.4 ) (29.3 ) Cash flows from financing activities: Repayment of finance lease — (1.1 ) — — (1.1 ) Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (6.2 ) — — — (6.2 ) Repurchase of common stock (40.6 ) — — — (40.6 ) Cash dividends paid to Parent — — (0.5 ) 0.5 — Cash dividends and dividend equivalents paid (29.8 ) — — — (29.8 ) Intercompany loans payable — (84.7 ) 1.3 83.4 — Net cash (used in) provided by financing activities (76.6 ) (85.8 ) 0.8 83.9 (77.7 ) Net increase (decrease) in cash, cash equivalents and restricted cash during the period — 48.5 (1.6 ) — 46.9 Cash, cash equivalents and restricted cash at beginning of period — 136.3 3.3 — 139.6 Cash, cash equivalents and restricted cash at end of period $ — $ 184.8 $ 1.7 $ — $ 186.5 CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS (In millions of dollars) Nine Months Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Cash flows from operating activities: Net cash provided by operating activities $ 87.5 $ 78.5 $ 46.5 $ (100.0 ) $ 112.5 Cash flows from investing activities: Capital expenditures — (51.9 ) (1.2 ) — (53.1 ) Purchase of available for sale securities — (111.9 ) — — (111.9 ) Purchase of equity securities — (0.9 ) — — (0.9 ) Proceeds from disposition of available for sale securities — 208.7 — — 208.7 Cash payment for acquisition of Imperial Machine & Tool Co., net of cash received — — (43.3 ) — (43.3 ) Proceeds from disposition of property, plant and equipment — 0.6 — — 0.6 Intercompany loans receivable (20.2 ) (0.4 ) (1.1 ) 21.7 — Net cash (used in) provided by investing activities (20.2 ) 44.2 (45.6 ) 21.7 0.1 Cash flows from financing activities: Repayment of finance lease — (0.5 ) — — (0.5 ) Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (6.9 ) — — — (6.9 ) Repurchase of common stock (31.9 ) — — — (31.9 ) Cash dividends paid to Parent — (100.0 ) — 100.0 — Cash dividends and dividend equivalents paid (28.5 ) — — — (28.5 ) Intercompany loans payable — 21.4 0.3 (21.7 ) — Net cash (used in) provided by financing activities (67.3 ) (79.1 ) 0.3 78.3 (67.8 ) Net increase in cash, cash equivalents and restricted cash during the period — 43.6 1.2 — 44.8 Cash, cash equivalents and restricted cash at beginning of period — 61.3 3.0 — 64.3 Cash, cash equivalents and restricted cash at end of period $ — $ 104.9 $ 4.2 $ — $ 109.1

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Dividend Declaration . On October 15, 2019 , we announced that our Board of Directors declared a cash dividend of $0.60 per common share. As such, we expect to pay approximately $9.6 million (including dividend equivalents) on or about November 15, 2019 to stockholders of record and the holders of certain restricted stock units at the close of business on October 25, 2019 .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Principles of Consolidation and Basis of Presentation	Principles of Consolidation and Basis of Presentation. The accompanying unaudited consolidated financial statements include the accounts of our wholly owned subsidiaries and are prepared in accordance with United States generally accepted accounting principles ("GAAP") and the rules and regulations of the Securities and Exchange Commission ("SEC") applicable for interim periods and, therefore, do not include all information and footnotes required by GAAP for complete financial statements. In management's opinion, all adjustments (which include normal recurring adjustments) considered necessary for a fair presentation have been included. The results of operations for our interim periods are not necessarily indicative of the results of operations that may be achieved for the entire 2019 fiscal year. The financial information as of December 31, 2018 is derived from our audited consolidated financial statements and footnotes included in our Annual Report on Form 10-K for the year ended December 31, 2018 .
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements.
Fair Value Measurements	Fair Value Measurements. We apply the fair value hierarchy established by GAAP for the recognition and measurement of certain financial assets and liabilities. An asset or liability's fair value classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. In determining fair value, we utilize valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible and consider counterparty risk in our assessment of fair value. We also review the underlying inputs that are significant to the fair value measurement of financial instruments to determine if a transfer among hierarchy levels is appropriate. We historically have not had significant transfers into or out of each hierarchy level. Financial assets and liabilities that we measure at fair value each period include our derivative instruments, equity investments related to our deferred compensation plan and debt investment securities classified as available for sale securities (see Note 4 and Note 5 ). Additionally, we measure at fair value once each year at December 31 our Canadian defined benefit pension plan and the plan assets of the Salaried VEBA (defined in Note 4 ). In determining the fair value of the plan assets at an annual period end, we utilize primarily the results of valuations supplied by the investment advisors responsible for managing the assets of each plan, which we independently review for reasonableness. We record our remaining financial assets and liabilities at carrying value. For a majority of our non-financial assets and liabilities, which include goodwill, intangible assets, inventories and property, plant and equipment, we are not required to measure their fair value on a recurring basis. However, if certain triggering events occur (or at least annually for goodwill), an evaluation of the affected non-financial asset or liability will be required, which could result in a reduction to the carrying amount of such asset or liability. None of our non-financial assets and liabilities subject to fair value assessments on a non-recurring basis required a material adjustment to the carrying amount of such assets and liabilities for the quarter and nine months ended September 30, 2019 .
Inventories	Inventories. Inventories are stated at the lower of cost or market value. Finished products, work-in-process and raw material inventories are stated on the last-in, first-out ("LIFO") basis. At September 30, 2019 and December 31, 2018 , the current cost of our inventory exceeded its stated LIFO value by $17.5 million and $31.7 million , respectively. Other inventories are stated on the first-in, first-out basis and consist of operating supplies, which are materials and supplies to be consumed during the production process. Inventory costs consist of material, labor and manufacturing overhead, including depreciation. Abnormal costs, such as idle facility expenses, freight, handling costs and spoilage, are accounted for as current period charges (see Note 2 for the components of inventories).
Replacement Parts	Replacement Parts. Replacement parts consist of preventative maintenance and capital spare parts, which are stated on the first-in, first-out basis. Replacement parts are recorded within Prepaid expenses and other current assets or Other assets depending on whether or not the expected utilization of the replacement parts is to occur within the current operating cycle.
Property, Plant and Equipment - Net	Property, Plant and Equipment, Net. Property, plant and equipment, net, is recorded at cost and includes construction in progress (see Note 2 ). Interest related to the construction of qualifying assets is capitalized as part of the construction costs. The amount of interest expense capitalized as construction in progress was $0.4 million for each of the quarters ended September 30, 2019 and September 30, 2018 . The amount of interest expense capitalized as construction in progress was $1.3 million for each of the nine months ended September 30, 2019 and September 30, 2018 . Depreciation is computed using the straight-line method at rates based on the estimated useful lives of the various classes of assets. Finance lease assets and leasehold improvements are depreciated on a straight-line basis over the shorter of the estimated useful lives of the assets or the lease term. We classify assets as held for sale only when an asset is being actively marketed and expected to sell within 12 months. Assets held for sale are initially measured at the lesser of the assets' carrying amount and the fair value less costs to sell.
Derivative Financial Instruments	Derivative Financial Instruments. Consistent with guidelines established by management and approved by our Board of Directors, we use derivative financial instruments to mitigate our exposure to changes in the market price of aluminum, alloying metals and energy, and, to a lesser extent, to foreign currency exchange rates. We do not use derivative financial instruments for trading or other speculative purposes. Hedging transactions are executed centrally on behalf of all of our operations to minimize transaction costs, monitor consolidated net exposures and allow for increased responsiveness to changes in market factors. We reflect the fair value of all of our derivative instruments on our Consolidated Balance Sheets (see Note 5 ). The fair value of hedges settling within one year is included in Prepaid expenses and other current assets or Other accrued liabilities. The fair value of hedges settling beyond one year is included in Other assets or Long-term liabilities. We designate our aluminum and energy derivatives and our forward swap contracts for zinc and copper ("Alloying Metals") used in our fabrication operations as cash flow hedges. Unrealized gains and losses associated with our cash flow hedges are deferred in Other comprehensive (loss) income, net of tax, and reclassified to Cost of products sold, excluding depreciation and amortization and other items ("COGS") when such hedges settle (see Note 5 ).
Self Insurance of Workers' Compensation and Employee Healthcare Liabilities	Self Insurance of Workers' Compensation and Employee Healthcare Liabilities . We self-insure the majority of the costs of workers' compensation benefits and employee healthcare benefits and rely on insurance coverage to protect us from large losses on individual claims. Workers' compensation liabilities are based on a combination of estimates for: (i) incurred-but-not-reported claims and (ii) the ultimate expense of incurred claims. Such estimates are based on judgment, using our historical claims data and information and analysis provided by actuarial and claims advisors, our insurance carriers and other professionals. Our undiscounted workers' compensation liabilities were estimated at $28.0 million and $27.6 million as of September 30, 2019 and December 31, 2018 , respectively. However, we accounted for our workers' compensation accrued liabilities on a discounted basis (see Note 2 ), using a discount rate of 1.75% and 3.00% at September 30, 2019 and December 31, 2018 , respectively. Accrued liabilities for employee healthcare benefits, which are estimates of unpaid incurred medical and prescription drug costs as provided by our healthcare administrators, were $3.3 million and $3.6 million as of September 30, 2019 and December 31, 2018 , respectively.
Short-Term Incentive Plans (STI Plans)	Short-Term Incentive Plans ("STI Plans"). We have annual short-term incentive compensation plans for senior management and certain other employees payable at our election in cash, shares of common stock or a combination of cash and shares of common stock. Amounts earned under STI Plans are based on our adjusted earnings before interest, taxes, depreciation and amortization ("Adjusted EBITDA"), modified for certain safety, quality, delivery, cost and individual performance factors. The Adjusted EBITDA targets are determined based on the return on adjusted net assets. Most of our production facilities have similar programs for both hourly and salaried employees. As of September 30, 2019 , we had a liability of $6.4 million recorded within Accrued salaries, wages and related expenses for estimated probable future payments relating to the nine month performance period of our 2019 STI Plan.
Long-Term Incentive Programs (LTI Programs)	Long-Term Incentive Programs. Executive officers and other key employees of the Company, as well as non-employee directors of the Company, are eligible to participate in the Kaiser Aluminum Corporation 2016 Equity and Incentive Compensation Plan approved by stockholders on May 26, 2016 ("2016 Plan"). At September 30, 2019 , 481,282 shares were available for awards under the 2016 Plan. We issue new shares of our common stock upon vesting under the 2016 Plan.
New Accounting Pronouncements	Adoption of New Accounting Pronouncements ASU No. 2016-02, Leases (Topic 842): Amendments to the Financial Accounting Standards Board Accounting Standards Codification ("ASU 2016-02"), was issued in February 2016 (with amendments issued in 2018) and requires lessees to recognize a right-of-use asset and a lease liability for virtually all of their leases (other than leases that meet the definition of a short-term lease). For income statement purposes, a dual model was retained, requiring leases to be classified as either operating or finance. Operating leases will result in straight-line expense (similar to operating leases under the previous guidance) while finance leases will result in a front-loaded expense pattern (similar to capital leases under the previous guidance). We adopted ASU 2016-02 and its subsequent amendments (together "ASC 842") during the quarter ended March 31, 2019 using the transition approach provided for under ASU No. 2018-11, Leases (Topic 842): Targeted Improvements , which allowed us to apply the new lease standard as of January 1, 2019, rather than the beginning of the earliest period presented. We elected the package of practical expedients, which permitted us to: (i) not reassess whether any of our contracts contained leases; (ii) carry forward the historical lease classification of our existing leases; and (iii) not reassess initial direct costs for our existing leases. We did not elect to apply the hindsight practical expedient when determining lease term and assessing impairment of right-of-use assets. Due to our adoption of ASC 842, we recorded an operating lease right-of-use asset of $29.0 million , a current operating lease liability of $4.1 million and a long-term operating lease liability of $27.4 million on our Consolidated Balance Sheets as of January 1, 2019. There was no cumulative-effect adjustment to Retained earnings required. The standard did not materially impact our consolidated net earnings and had no impact on cash flows. Comparative information in this Report has not been adjusted and continues to be reported under the previous lease accounting rules. See Note 3 for details of the significant changes and quantitative impacts of the changes, as well as other required disclosures related to our adoption of ASC 842. There were no material impacts on our consolidated financial statements resulting from our adoption during the nine months ended September 30, 2019 of: (i) ASU No. 2018-07, Compensation-Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting; (ii) ASU No. 2018-08, Not-for-Profit Entities (Topic 958): Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made; and (iii) ASU No. 2019-07, Codification Updates to SEC Sections: Amendments to SEC Paragraphs Pursuant to SEC Final Rule Releases No. 33-10532, Disclosure Update and Simplification, and Nos. 33-10231 and 33-10442, Investment Company Reporting Modernization, and Miscellaneous Updates. Accounting Pronouncements Issued But Not Yet Adopted ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"), was issued in June 2016. Under ASU 2016-13, existing guidance on reporting credit losses for trade and other receivables and available for sale debt securities will be replaced with a new forward-looking "expected loss" model that generally will result in the earlier recognition of allowances for losses. We are currently in the process of evaluating the impact of adopting ASU 2016-13 in 2020, but do not expect it to have a material impact on our consolidated financial statements. ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract ("ASU 2018-15"), was issued in August 2018. Under ASU 2018-15, requirements for capitalizing implementation costs incurred in a hosting arrangement (cloud computing) that is a service contract are to be aligned with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. We are currently in the process of evaluating the impact of adopting ASU 2018-15 in 2020, but do not expect it to have a material impact on our consolidated financial statements.
Leases	We determine whether an agreement is a lease at inception. We have operating and finance leases for equipment and real estate that primarily have fixed lease payments. Our leases have remaining lease terms of approximately one to 15 years , some of which may include options to extend the lease for up to 20 years , and some of which may include options to terminate the lease within one year . None of our options to extend or terminate are reasonably certain of being exercised, and are therefore not included in our determination of lease assets and liabilities. Short-term leases with an initial term of 12 months or less are not recorded on our Consolidated Balance Sheets. As most of our leases do not provide an implicit rate, we use information available at the lease commencement date in determining an incremental borrowing rate when calculating our operating lease assets and operating lease liabilities. In determining the inputs to the incremental borrowing rate calculation, we make judgments about the value of the leased asset, our credit rating and the lease term, including the probability of our exercising options to extend or terminate the underlying lease. Additionally, we make judgments around contractual asset substitution rights in determining whether a contract contains a lease. We have lease agreements with lease and non-lease components, which are generally accounted for separately. These non-lease components include items such as common area maintenance, taxes and insurance for our real estate leases, as well as maintenance charges related to our equipment leases. We have, however, applied the practical expedient within ASU 2016-02 to not separate lease and non-lease components to our embedded supply system equipment leases and have therefore accounted for both lease and non-lease components in determining the lease assets and liabilities. Many of our equipment leases contain clauses that require us to return the equipment with certain functionality intact. We account for these costs as residual value guarantees when the guarantee becomes probable of being owed. Our lease agreements do not contain any material restrictive covenants.

Supplemental Balance Sheet In_2

Supplemental Balance Sheet Information (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Balance Sheet Disclosures	Supplemental Balance Sheet Information September 30, 2019 December 31, 2018 (In millions of dollars) Cash and Cash Equivalents Cash and money market funds $ 29.3 $ 22.9 Commercial paper 142.8 102.7 Total $ 172.1 $ 125.6 Trade Receivables, Net Billed trade receivables $ 188.9 $ 179.5 Unbilled trade receivables — 1.1 Trade receivables, gross 188.9 180.6 Allowance for doubtful receivables (0.8 ) (0.8 ) Trade receivables, net $ 188.1 $ 179.8 Inventories Finished products $ 41.4 $ 48.0 Work-in-process 80.5 85.6 Raw materials 63.7 75.0 Operating supplies 6.9 6.5 Total $ 192.5 $ 215.1 Property, Plant and Equipment, Net Land and improvements $ 21.4 $ 21.4 Buildings and leasehold improvements 99.2 97.0 Machinery and equipment 797.9 755.6 Construction in progress 35.4 43.6 Property, plant and equipment, gross 953.9 917.6 Accumulated depreciation (341.2 ) (307.4 ) Assets held for sale 1.6 1.6 Property, plant and equipment, net $ 614.3 $ 611.8 Other Accrued Liabilities Uncleared cash disbursements $ 3.7 $ 4.8 Accrued income taxes and taxes payable 8.0 6.5 Accrued annual contribution to Salaried VEBA — 2.1 Accrued interest 8.4 2.9 Accrued environmental – Note 7 4.3 2.6 Other – Note 3 and Note 5 25.7 25.1 Total $ 50.1 $ 44.0 September 30, 2019 December 31, 2018 (In millions of dollars) Long-Term Liabilities Workers' compensation accruals $ 26.9 $ 24.6 Long-term environmental accrual – Note 7 12.2 14.3 Other long-term liabilities 26.3 27.5 Total $ 65.4 $ 66.4

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Schedule of Lease Terms and Discount Rates	The following table presents lease terms and discount rates as of September 30, 2019 : Finance Leases Operating Leases Weighted-average lease term (in years): 6.0 10.5 Weighted-average discount rate: 4.5 % 5.9 %
Schedule of Lease Assets and Liabilities	The following table summarizes the classification of lease assets and lease liabilities on our Consolidated Balance Sheet as of the period presented (in millions of dollars): Leases Classification September 30, 2019 Assets Operating lease assets Operating lease assets $ 26.3 Finance lease assets Property, plant and equipment, net 6.8 Total lease assets $ 33.1 Liabilities Current: Operating lease liabilities Other accrued liabilities $ 3.9 Finance lease liabilities Other accrued liabilities 1.2 Non-current: Operating lease liabilities Long-term portion of operating lease liabilities 25.6 Finance lease liabilities Long-term liabilities 5.6 Total lease liabilities $ 36.3
Schedule of Lease Cost Classification	The following table summarizes the components of lease cost on our Statements of Consolidated Income for the periods presented (in millions of dollars): Lease Cost Quarter Ended September 30, 2019 Nine Months Ended September 30, 2019 Operating lease cost $ 1.8 $ 5.6 Short-term lease cost 0.3 0.8 Finance lease cost: Amortization of leased assets 0.5 1.2 Interest on lease liabilities — 0.2 Total lease cost $ 2.6 $ 7.8
Lease Liability Maturity Schedule	The following table presents the maturity of our lease liabilities as of September 30, 2019 (in millions of dollars): Maturity of Lease Liabilities Finance Leases Operating Leases Remainder of 2019 $ 0.4 $ 1.3 2020 1.6 5.2 2021 1.4 4.4 2022 1.2 3.6 2023 1.1 3.4 2024 0.7 3.3 2025 and thereafter 1.4 18.9 Total minimum lease payments $ 7.8 $ 40.1 Less: interest (1.0 ) (10.6 ) Present value $ 6.8 $ 29.5
Schedule of Future Minimum Rental Payments	The following table presents minimum rental commitments at December 31, 2018 (in millions of dollars): Year Ended December 31, Finance Leases Operating Leases 2019 $ 1.7 $ 6.1 2020 1.4 3.7 2021 1.2 2.8 2022 1.1 2.4 2023 1.0 2.2 2024 and thereafter 1.8 20.8 Total minimum lease payments $ 8.2 $ 38.0 Less: interest (1.2 ) Present value 1 $ 7.0 _________________________ 1. Of the $7.0 million in finance lease obligations as of December 31, 2018, $1.4 million was included in Other accrued liabilities and $5.6 million was included in Long-term liabilities. Assets recorded under finance leases and the accumulated amortization thereon were $8.3 million and $1.3 million , respectively, as of December 31, 2018.

Employee Benefits (Tables)

Employee Benefits (Tables)	9 Months Ended
	Sep. 30, 2019
Retirement Benefits [Abstract]
Schedule of Total Expense (Income) Related to Benefit Plans	The following tables present the total expense related to all benefit plans for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Defined contribution plans 1 $ 1.7 $ 1.7 $ 7.3 $ 7.3 Deferred compensation plan 1 0.3 0.2 1.3 1.2 Multiemployer pension plans 1 1.3 1.2 3.7 3.5 Net periodic postretirement benefit cost relating to Salaried VEBA 2 1.6 1.4 4.9 4.5 Total $ 4.9 $ 4.5 $ 17.2 $ 16.5 ____________________ 1 Substantially all of the expense related to employee benefits are in COGS with the remaining balance in Selling, general, administrative, research and development ("SG&A and R&D"). 2 The current service cost component of Net periodic postretirement benefit cost relating to Salaried VEBA is included within our Statements of Consolidated Income in SG&A and R&D for all periods presented. All other components of Net periodic postretirement benefit cost relating to Salaried VEBA are included within Other (expense) income, net, on our Statements of Consolidated Income.
Schedule of Net Benefit Costs	The following table presents the components of Net periodic postretirement benefit cost relating to Salaried VEBA for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Salaried VEBA 1 : Interest cost $ 0.8 $ 0.7 $ 2.4 $ 2.1 Expected return on plan assets (0.7 ) (0.8 ) (2.0 ) (2.2 ) Amortization of prior service cost 2 1.4 1.3 4.2 4.0 Amortization of net actuarial loss 0.1 0.2 0.3 0.6 Total net periodic postretirement benefit cost relating to Salaried VEBA $ 1.6 $ 1.4 $ 4.9 $ 4.5 ____________________ 1 The service cost was insignificant for all periods presented. 2 We amortize prior service cost on a straight-line basis over the average remaining years of service to full eligibility for benefits of the active plan participants.

Derivatives, Hedging Programs_2

Derivatives, Hedging Programs and Other Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of material derivative positions	The following table summarizes our derivative positions at September 30, 2019 : Aluminum Maturity Period (month/year) Notional Amount of Contracts (mmlbs) Fixed price purchase contracts 10/19 through 12/21 83.1 Fixed price sales contracts 11/19 through 9/21 0.8 Midwest premium swap contracts 1 10/19 through 12/21 57.6 Alloying Metals Maturity Period (month/year) Notional Amount of Contracts (mmlbs) Fixed price purchase contracts 10/19 through 12/21 12.9 Natural Gas 2 Maturity Period (month/year) Notional Amount of Contracts (mmbtu) Fixed price purchase contracts 10/19 through 12/24 7,930,000 Electricity 3 Maturity Period (month/year) Notional Amount of Contracts (Mwh) Fixed price purchase contracts 1/20 through 12/21 394,680 Euro 4 Maturity Period (month/year) Notional Amount of Contracts (euro) Fixed price purchase contracts 10/19 through 1/20 3,189,200 ____________________ 1 Regional premiums represent the premium over the London Metal Exchange price for primary aluminum which is incurred on our purchases of primary aluminum. 2 As of September 30, 2019 , we had derivative and/or physical delivery commitments with energy companies in place to cover exposure to fluctuations in prices for approximately 72% of the expected natural gas purchases for the remainder of 2019 , 68% of the expected natural gas purchases for both 2020 and 2021 , 83% of the expected natural gas purchases for both 2022 and 2023 and 77% of the expected natural gas purchases for 2024. 3 As of September 30, 2019 , we had derivative and/or physical delivery commitments with energy companies in place to cover exposure to fluctuations in prices for approximately 54% of our expected electricity purchases for the remainder of 2019 , 55% of our expected electricity purchases for 2020 and 46% of our expected electricity purchases for 2021 . 4 We are exposed to foreign currency exchange risk related to firm-price agreements for equipment purchases from foreign manufacturers. We use non-designated foreign currency forward contracts designed to line up with the timing and amounts of scheduled payments to the foreign equipment manufacturers to mitigate our exposure to currency exchange rate fluctuations on these purchases.
Summary of realized and unrealized gains and losses	The amount of loss (gain) included on our Statements of Consolidated Income (all within COGS) associated with all derivative contracts consisted of the following for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended 2019 2018 2019 2018 Total amounts of income and expense line items presented in our Statements of Consolidated Income in which the effects of hedges are recorded $ 298.6 $ 323.3 $ 917.2 $ 983.4 Loss (gain) recognized in income related to cash flow hedges: Aluminum $ 4.8 $ 2.1 $ 13.5 $ (1.2 ) Alloying metals 0.5 1.0 0.7 0.4 Natural gas 0.1 — 0.1 (0.1 ) Total loss (gain) recognized in income related to cash flow hedges $ 5.4 $ 3.1 $ 14.3 $ (0.9 ) Loss recognized in income related to non-designated hedges: Foreign currency $ 0.1 $ — $ 0.1 $ — Total loss recognized in income related to non-designated hedges $ 0.1 $ — $ 0.1 $ —
Fair Value of Derivative Assets and Liabilities Measured on Recurring Basis	The following table presents the fair value of our derivative financial instruments as of the periods presented (in millions of dollars): September 30, 2019 December 31, 2018 Derivative Assets Derivative Liabilities Net Amount Derivative Assets Derivative Liabilities Net Amount Cash Flow Hedges: Aluminum – Fixed price purchase contracts $ — $ (10.2 ) $ (10.2 ) $ 0.1 $ (13.2 ) $ (13.1 ) Fixed price sales contracts 0.1 — 0.1 0.1 — 0.1 Midwest premium swap contracts 0.6 (0.1 ) 0.5 3.2 (0.5 ) 2.7 Alloying Metals – Fixed price purchase contracts — (2.0 ) (2.0 ) — (1.7 ) (1.7 ) Natural gas – Fixed price purchase contracts — (2.0 ) (2.0 ) 0.2 (0.5 ) (0.3 ) Electricity – Fixed price purchase contracts 1.5 (1.5 ) — 0.7 — 0.7 Non-Designated Hedges: Foreign currency – Fixed price purchase contracts — (0.1 ) (0.1 ) — — — Total $ 2.2 $ (15.9 ) $ (13.7 ) $ 4.3 $ (15.9 ) $ (11.6 ) The following table presents the total amounts of derivative assets and liabilities on our Consolidated Balance Sheets as of the periods presented (in millions of dollars): September 30, 2019 December 31, 2018 Derivative assets: Prepaid expenses and other current assets $ 1.2 $ 3.4 Other assets 1.0 0.9 Total derivative assets $ 2.2 $ 4.3 Derivative liabilities: Other accrued liabilities $ (12.8 ) $ (13.2 ) Long-term liabilities (3.1 ) (2.7 ) Total derivative liabilities $ (15.9 ) $ (15.9 )
Fair Value, Non-Derivative Assets Measured on Recurring Basis	The following table classifies our other financial assets under the appropriate level of the fair value hierarchy as of September 30, 2019 (in millions of dollars): Level 1 Level 2 Level 3 Total Cash and cash equivalents 29.3 142.8 $ — $ 172.1 Short-term investments — 25.3 — 25.3 Total $ 29.3 $ 168.1 $ — $ 197.4 The following table classifies our other financial assets under the appropriate level of the fair value hierarchy as of December 31, 2018 (in millions of dollars): Level 1 Level 2 Level 3 Total Cash and cash equivalents 22.9 102.7 $ — $ 125.6 Short-term investments — 36.7 — 36.7 Total $ 22.9 $ 139.4 $ — $ 162.3

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table presents the changes in the accumulated balances for each component of AOCI for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Defined Benefit Pension Plan and Salaried VEBA: Beginning balance $ (33.4 ) $ (36.1 ) $ (35.6 ) $ (38.5 ) Amortization of net actuarial loss 1 0.1 0.2 0.3 0.6 Amortization of prior service cost 1 1.4 1.3 4.2 4.0 Less: income tax expense 2 (0.3 ) (0.4 ) (1.1 ) (1.1 ) Net amortization reclassified from AOCI to Net income 1.2 1.1 3.4 3.5 Other comprehensive income, net of tax 1.2 1.1 3.4 3.5 Ending balance $ (32.2 ) $ (35.0 ) $ (32.2 ) $ (35.0 ) Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Available for Sale Securities: Beginning balance $ — $ 0.6 $ 0.3 $ 0.9 Unrealized gain on available for sale securities 1.0 1.3 2.7 3.6 Less: income tax expense (0.3 ) (0.3 ) (0.7 ) (0.9 ) Net unrealized gain on available for sale securities 0.7 1.0 2.0 2.7 Reclassification of unrealized gain upon sale of available for sale securities 3 (0.9 ) (1.6 ) (3.0 ) (4.3 ) Less: income tax benefit 2 0.3 0.4 0.8 1.1 Net gain reclassified from AOCI to Net income (0.6 ) (1.2 ) (2.2 ) (3.2 ) Other comprehensive income (loss), net of tax 0.1 (0.2 ) (0.2 ) (0.5 ) Ending balance $ 0.1 $ 0.4 $ 0.1 $ 0.4 Cash Flow Hedges: Beginning balance $ (8.8 ) $ (3.5 ) $ (13.4 ) $ 0.5 Unrealized loss on cash flow hedges (8.4 ) (5.2 ) (11.1 ) (6.5 ) Less: income tax benefit 2.1 1.2 2.7 1.6 Net unrealized loss on cash flow hedges (6.3 ) (4.0 ) (8.4 ) (4.9 ) Reclassification of unrealized loss (gain) upon settlement of cash flow hedges 4 5.4 3.0 14.3 (1.0 ) Less: income tax (expense) benefit 2 (1.3 ) (0.7 ) (3.5 ) 0.2 Net loss (gain) reclassified from AOCI to Net income 4.1 2.3 10.8 (0.8 ) Other comprehensive (loss) income, net of tax (2.2 ) (1.7 ) 2.4 (5.7 ) Ending balance $ (11.0 ) $ (5.2 ) $ (11.0 ) $ (5.2 ) Foreign Currency Translation: Beginning balance $ (0.1 ) $ — $ (0.1 ) $ — Other comprehensive income, net of tax — — — — Ending balance $ (0.1 ) $ — $ (0.1 ) $ — Total AOCI ending balance $ (43.2 ) $ (39.8 ) $ (43.2 ) $ (39.8 ) ____________________ 1 Amounts amortized out of AOCI relating to Salaried VEBA adjustments were included within Other (expense) income, net, as a component of Net periodic postretirement benefit cost relating to Salaried VEBA. 2 Income tax amounts reclassified out of AOCI were included as a component of Income tax provision. 3 Amounts reclassified out of AOCI relating to sales of available for sale securities were included as a component of Other (expense) income, net. We use the specific identification method to determine the amount reclassified out of AOCI. 4 Amounts reclassified out of AOCI relating to cash flow hedges were included as a component of COGS. As of September 30, 2019 , we estimate a net mark-to-market loss before tax of $12.2 million in AOCI will be reclassified into Net income within the next 12 months.

Other (Expense) Income, Net (Ta

Other (Expense) Income, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Other Income and Expenses [Abstract]
Other Income, Net	Other (expense) income, net, consisted of the following for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Interest income $ 0.2 $ 0.1 $ 0.5 $ 0.2 Net periodic postretirement benefit cost relating to Salaried VEBA (1.6 ) (1.4 ) (4.9 ) (4.5 ) Realized gain on available for sale securities 0.9 1.6 3.0 4.3 Unrealized gain (loss) on equity securities 0.1 0.1 0.6 (0.3 ) All other (expense) income, net (0.4 ) 0.3 0.4 0.6 Other (expense) income, net $ (0.8 ) $ 0.7 $ (0.4 ) $ 0.3

Income Tax Matters (Tables)

Income Tax Matters (Tables)	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Tax Provision	The provision for in come taxes consisted of the following for the periods presented (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Domestic $ 8.5 $ 7.5 $ 24.7 $ 20.5 Foreign 0.2 0.7 1.1 1.4 Total $ 8.7 $ 8.2 $ 25.8 $ 21.9

Net Income Per Share and Stoc_2

Net Income Per Share and Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Calculation of basic and diluted earnings per share	The following table sets forth the computation of basic and diluted net income per share for the periods presented (in millions of dollars, except share and per share amounts): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Numerator: Net income $ 25.4 $ 21.7 $ 72.6 $ 68.1 Denominator – Weighted-average common shares outstanding (in thousands): Basic 15,956 16,573 16,042 16,654 Add: dilutive effect of non-vested common shares, restricted stock units and performance shares 1 169 210 193 228 Diluted 16,125 16,783 16,235 16,882 Net income per common share, Basic: $ 1.59 $ 1.31 $ 4.52 $ 4.09 Net income per common share, Diluted: $ 1.57 $ 1.29 $ 4.47 $ 4.03 ____________________ 1 During both the quarter and nine months ended September 30, 2019 , a total of seven thousand securities were excluded from the weighted-average diluted shares computation as their inclusion would have been anti-dilutive. There were no anti-dilutive securities during both the quarter and nine months ended September 30, 2018 .

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Nine Months Ended September 30, 2019 2018 (In millions of dollars) Interest paid $ 10.6 $ 10.6 Non-cash investing and financing activities (included in Accounts payable): Unpaid purchases of property and equipment $ 3.3 $ 5.8 Stock repurchases not yet settled $ 0.3 $ 0.4 Supplemental lease disclosures: Operating lease liabilities arising from obtaining operating lease assets $ 1.6 n/a Cash paid for amounts included in the measurement of operating lease liabilities $ 2.8 n/a Finance lease liabilities arising from obtaining finance lease assets $ 0.9 $ 0.3 September 30, 2019 September 30, 2018 (In millions of dollars) Components of cash, cash equivalents and restricted cash: Cash and cash equivalents $ 172.1 $ 94.3 Restricted cash included in Prepaid expenses and other current assets 1 0.3 0.3 Restricted cash included in Other assets 1 14.1 14.5 Total cash, cash equivalents and restricted cash presented on our Statements of Consolidated Cash Flows $ 186.5 $ 109.1 ____________________ 1

Business, Product and Geograp_2

Business, Product and Geographical Area Information and Concentration of Risk (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Schedule of net sales by end market segment applications	Net sales by end market applications and by timing of control transfer for the periods presented were as follows (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Net sales: Aero/HS products $ 198.9 $ 185.7 $ 586.8 $ 540.9 Automotive Extrusions 47.5 56.1 146.0 183.9 GE products 117.1 133.9 375.3 425.1 Other products 11.4 17.4 37.3 46.6 Total net sales $ 374.9 $ 393.1 $ 1,145.4 $ 1,196.5 Timing of revenue recognition: Products transferred at a point in time $ 115.9 $ 127.8 $ 378.7 $ 425.2 Products transferred over time 259.0 265.3 766.7 771.3 Total net sales $ 374.9 $ 393.1 $ 1,145.4 $ 1,196.5
Schedule of income taxes paid by geographical area	Geographic information for income taxes paid for the periods presented was as follows (in millions of dollars): Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Income taxes paid: Domestic $ 0.1 $ 0.4 $ 2.0 $ 1.3 Foreign 0.4 — 1.6 2.0 Total income taxes paid $ 0.5 $ 0.4 $ 3.6 $ 3.3
Schedule of information for contractual delivery of primary aluminum supply from major suppliers	Information about primary aluminum supply from our major suppliers for the periods presented was as follows: Quarter Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Percentage of total primary aluminum supply (lbs): Supply from our top five major suppliers 81 % 83 % 74 % 82 % Supply from our largest supplier 23 % 33 % 21 % 36 % Supply from our second and third largest suppliers combined 38 % 36 % 33 % 32 %

Condensed Guarantor and Non-G_2

Condensed Guarantor and Non-Guarantor Financial Information (Tables)	9 Months Ended
	Sep. 30, 2019
Guarantor and Non-Guarantor Financial Statement [Abstract]
Condensed Financial Statements	CONDENSED CONSOLIDATING BALANCE SHEET (In millions of dollars) September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated ASSETS Current assets: Cash and cash equivalents $ — $ 170.7 $ 1.4 $ — $ 172.1 Short-term investments — 25.3 — — 25.3 Receivables: Trade receivables, net — 183.2 4.9 — 188.1 Intercompany loans receivable 50.6 1.4 5.5 (57.5 ) — Other — 24.3 1.8 — 26.1 Contract assets — 43.6 2.5 — 46.1 Inventories — 183.1 9.4 — 192.5 Prepaid expenses and other current assets 0.3 17.7 0.4 — 18.4 Total current assets 50.9 649.3 25.9 (57.5 ) 668.6 Investments in and advances to subsidiaries 1,081.4 95.7 0.2 (1,177.3 ) — Property, plant and equipment, net — 580.6 33.7 — 614.3 Operating lease assets — 26.3 — — 26.3 Long-term intercompany loans receivable — — 17.0 (17.0 ) — Deferred tax assets, net — 3.3 — 3.0 6.3 Intangible assets, net — 22.6 7.7 — 30.3 Goodwill — 18.7 25.3 — 44.0 Other assets — 36.2 0.2 0.1 36.5 Total $ 1,132.3 $ 1,432.7 $ 110.0 $ (1,248.7 ) $ 1,426.3 LIABILITIES AND STOCKHOLDERS ' EQUITY Current liabilities: Accounts payable $ 1.5 $ 86.7 $ 5.6 $ — $ 93.8 Intercompany loans payable — 56.1 1.4 (57.5 ) — Accrued salaries, wages and related expenses — 30.3 1.6 — 31.9 Other accrued liabilities 8.3 46.1 0.5 (4.8 ) 50.1 Total current liabilities 9.8 219.2 9.1 (62.3 ) 175.8 Long-term portion of operating lease liabilities — 25.6 — — 25.6 Net liabilities of Salaried VEBA — 32.8 — — 32.8 Deferred tax liabilities — — 4.2 — 4.2 Long-term intercompany loans payable — 17.0 — (17.0 ) — Long-term liabilities — 61.8 3.6 — 65.4 Long-term debt 371.1 — — — 371.1 Total liabilities 380.9 356.4 16.9 (79.3 ) 674.9 Total stockholders' equity 751.4 1,076.3 93.1 (1,169.4 ) 751.4 Total $ 1,132.3 $ 1,432.7 $ 110.0 $ (1,248.7 ) $ 1,426.3 CONDENSED CONSOLIDATING BALANCE SHEET (In millions of dollars) December 31, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated ASSETS Current assets: Cash and cash equivalents $ — $ 122.6 $ 3.0 $ — $ 125.6 Short-term investments — 36.7 — — 36.7 Receivables: Trade receivables, net — 174.0 5.8 — 179.8 Intercompany receivables 143.7 0.1 4.3 (148.1 ) — Other — 23.3 2.3 — 25.6 Contract assets — 52.0 2.9 — 54.9 Inventories — 203.0 12.1 — 215.1 Prepaid expenses and other current assets 0.1 18.4 0.4 — 18.9 Total current assets 143.8 630.1 30.8 (148.1 ) 656.6 Investments in and advances to subsidiaries 974.7 94.9 0.2 (1,069.8 ) — Property, plant and equipment, net — 577.4 34.4 — 611.8 Long-term intercompany receivables — — 9.8 (9.8 ) — Deferred tax assets, net — 32.9 — 3.0 35.9 Intangible assets, net — 23.6 8.8 — 32.4 Goodwill — 18.8 25.2 — 44.0 Other assets — 38.6 — — 38.6 Total $ 1,118.5 $ 1,416.3 $ 109.2 $ (1,224.7 ) $ 1,419.3 LIABILITIES AND STOCKHOLDERS ' EQUITY Current liabilities: Accounts payable $ 4.9 $ 109.6 $ 6.9 $ — $ 121.4 Intercompany payable — 148.0 0.1 (148.1 ) — Accrued salaries, wages and related expenses — 38.3 1.8 — 40.1 Other accrued liabilities 2.8 46.7 0.8 (6.3 ) 44.0 Total current liabilities 7.7 342.6 9.6 (154.4 ) 205.5 Net liabilities of Salaried VEBA — 32.4 — — 32.4 Deferred tax liabilities — — 4.2 — 4.2 Long-term intercompany payable — 9.8 — (9.8 ) — Long-term liabilities — 63.3 3.1 — 66.4 Long-term debt 370.4 — — — 370.4 Total liabilities 378.1 448.1 16.9 (164.2 ) 678.9 Total stockholders' equity 740.4 968.2 92.3 (1,060.5 ) 740.4 Total $ 1,118.5 $ 1,416.3 $ 109.2 $ (1,224.7 ) $ 1,419.3 CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (In millions of dollars) Quarter Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Net sales $ — $ 365.2 $ 25.6 $ (15.9 ) $ 374.9 Costs and expenses: Cost of products sold, excluding depreciation and amortization and other items — 293.4 20.7 (15.5 ) 298.6 Depreciation and amortization — 11.3 1.0 — 12.3 Selling, general, administrative, research and development 1.5 19.6 2.6 (0.4 ) 23.3 Total costs and expenses 1.5 324.3 24.3 (15.9 ) 334.2 Operating (loss) income (1.5 ) 40.9 1.3 — 40.7 Other (expense) income: Interest expense (5.3 ) (0.6 ) — 0.1 (5.8 ) Other (expense) income, net — (0.8 ) 0.1 (0.1 ) (0.8 ) (Loss) income before income taxes (6.8 ) 39.5 1.4 — 34.1 Income tax provision — (10.0 ) (0.4 ) 1.7 (8.7 ) Earnings in equity of subsidiaries 32.2 1.0 — (33.2 ) — Net income $ 25.4 $ 30.5 $ 1.0 $ (31.5 ) $ 25.4 Comprehensive income $ 24.5 $ 29.6 $ 1.0 $ (30.6 ) $ 24.5 CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (In millions of dollars) Quarter Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Net sales $ — $ 385.9 $ 33.7 $ (26.5 ) $ 393.1 Costs and expenses: Cost of products sold, excluding depreciation and amortization and other items — 317.9 31.5 (26.1 ) 323.3 Depreciation and amortization — 10.5 0.5 — 11.0 Selling, general, administrative, research and development 1.0 22.8 0.5 (0.4 ) 23.9 Total costs and expenses 1.0 351.2 32.5 (26.5 ) 358.2 Operating (loss) income (1.0 ) 34.7 1.2 — 34.9 Other (expense) income: Interest expense (5.4 ) (0.4 ) — 0.1 (5.7 ) Other income, net — 0.6 0.2 (0.1 ) 0.7 (Loss) income before income taxes (6.4 ) 34.9 1.4 — 29.9 Income tax provision — (9.0 ) (0.8 ) 1.6 (8.2 ) Earnings in equity of subsidiaries 28.1 0.6 — (28.7 ) — Net income $ 21.7 $ 26.5 $ 0.6 $ (27.1 ) $ 21.7 Comprehensive income $ 20.9 $ 25.7 $ 0.6 $ (26.3 ) $ 20.9 CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (In millions of dollars) Nine Months Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Net sales $ — $ 1,117.8 $ 78.2 $ (50.6 ) $ 1,145.4 Costs and expenses: Cost of products sold, excluding depreciation and amortization and other items — 898.4 68.2 (49.4 ) 917.2 Depreciation and amortization — 33.3 3.0 — 36.3 Selling, general, administrative, research and development 4.0 67.4 5.5 (1.2 ) 75.7 Other operating charges, net — 0.1 — — 0.1 Total costs and expenses 4.0 999.2 76.7 (50.6 ) 1,029.3 Operating (loss) income (4.0 ) 118.6 1.5 — 116.1 Other (expense) income: Interest expense (15.9 ) (1.7 ) — 0.3 (17.3 ) Other (expense) income, net — (0.6 ) 0.5 (0.3 ) (0.4 ) (Loss) income before income taxes (19.9 ) 116.3 2.0 — 98.4 Income tax provision — (30.0 ) (0.7 ) 4.9 (25.8 ) Earnings in equity of subsidiaries 92.5 1.3 — (93.8 ) — Net income $ 72.6 $ 87.6 $ 1.3 $ (88.9 ) $ 72.6 Comprehensive income $ 78.2 $ 93.2 $ 1.3 $ (94.5 ) $ 78.2 CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (In millions of dollars) Nine Months Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Net sales $ — $ 1,168.5 $ 103.3 $ (75.3 ) $ 1,196.5 Costs and expenses: Cost of products sold, excluding depreciation and amortization and other items — 962.9 93.5 (73.0 ) 983.4 Depreciation and amortization — 30.8 1.6 — 32.4 Selling, general, administrative, research and development 3.7 67.8 4.7 (2.3 ) 73.9 Other operating charges, net — 0.1 — — 0.1 Total costs and expenses 3.7 1,061.6 99.8 (75.3 ) 1,089.8 Operating (loss) income (3.7 ) 106.9 3.5 — 106.7 Other (expense) income: Interest expense (15.9 ) (1.5 ) — 0.4 (17.0 ) Other income, net — 0.4 0.3 (0.4 ) 0.3 (Loss) income before income taxes (19.6 ) 105.8 3.8 — 90.0 Income tax provision — (25.3 ) (1.4 ) 4.8 (21.9 ) Earnings in equity of subsidiaries 87.7 2.4 — (90.1 ) — Net income $ 68.1 $ 82.9 $ 2.4 $ (85.3 ) $ 68.1 Comprehensive income $ 65.4 $ 80.2 $ 2.4 $ (82.6 ) $ 65.4 CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS (In millions of dollars) Nine Months Ended September 30, 2019 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Cash flows from operating activities: Net cash (used in) provided by operating activities $ (16.5 ) $ 163.6 $ 7.3 $ (0.5 ) $ 153.9 Cash flows from investing activities: Capital expenditures — (39.4 ) (1.3 ) — (40.7 ) Purchase of available for sale securities — (56.3 ) — — (56.3 ) Purchase of equity securities — (0.7 ) — — (0.7 ) Proceeds from disposition of available for sale securities — 68.2 — — 68.2 Proceeds from disposal of property, plant and equipment — 0.2 — — 0.2 Intercompany loans receivable 93.1 (1.3 ) (8.4 ) (83.4 ) — Net cash provided by (used in) investing activities 93.1 (29.3 ) (9.7 ) (83.4 ) (29.3 ) Cash flows from financing activities: Repayment of finance lease — (1.1 ) — — (1.1 ) Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (6.2 ) — — — (6.2 ) Repurchase of common stock (40.6 ) — — — (40.6 ) Cash dividends paid to Parent — — (0.5 ) 0.5 — Cash dividends and dividend equivalents paid (29.8 ) — — — (29.8 ) Intercompany loans payable — (84.7 ) 1.3 83.4 — Net cash (used in) provided by financing activities (76.6 ) (85.8 ) 0.8 83.9 (77.7 ) Net increase (decrease) in cash, cash equivalents and restricted cash during the period — 48.5 (1.6 ) — 46.9 Cash, cash equivalents and restricted cash at beginning of period — 136.3 3.3 — 139.6 Cash, cash equivalents and restricted cash at end of period $ — $ 184.8 $ 1.7 $ — $ 186.5 CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS (In millions of dollars) Nine Months Ended September 30, 2018 Parent Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated Cash flows from operating activities: Net cash provided by operating activities $ 87.5 $ 78.5 $ 46.5 $ (100.0 ) $ 112.5 Cash flows from investing activities: Capital expenditures — (51.9 ) (1.2 ) — (53.1 ) Purchase of available for sale securities — (111.9 ) — — (111.9 ) Purchase of equity securities — (0.9 ) — — (0.9 ) Proceeds from disposition of available for sale securities — 208.7 — — 208.7 Cash payment for acquisition of Imperial Machine & Tool Co., net of cash received — — (43.3 ) — (43.3 ) Proceeds from disposition of property, plant and equipment — 0.6 — — 0.6 Intercompany loans receivable (20.2 ) (0.4 ) (1.1 ) 21.7 — Net cash (used in) provided by investing activities (20.2 ) 44.2 (45.6 ) 21.7 0.1 Cash flows from financing activities: Repayment of finance lease — (0.5 ) — — (0.5 ) Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (6.9 ) — — — (6.9 ) Repurchase of common stock (31.9 ) — — — (31.9 ) Cash dividends paid to Parent — (100.0 ) — 100.0 — Cash dividends and dividend equivalents paid (28.5 ) — — — (28.5 ) Intercompany loans payable — 21.4 0.3 (21.7 ) — Net cash (used in) provided by financing activities (67.3 ) (79.1 ) 0.3 78.3 (67.8 ) Net increase in cash, cash equivalents and restricted cash during the period — 43.6 1.2 — 44.8 Cash, cash equivalents and restricted cash at beginning of period — 61.3 3.0 — 64.3 Cash, cash equivalents and restricted cash at end of period $ — $ 104.9 $ 4.2 $ — $ 109.1

Summary of Significant Accoun_3

Summary of Significant Accounting Policies, Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Jan. 01, 2019	Dec. 31, 2017
Significant accounting policies
Operating lease assets	$ 26.3		$ 26.3		$ 0
Operating lease liabilities, current	3.9		3.9
Excess of current cost over the stated LIFO value of inventory	17.5		17.5		31.7
Interest expense capitalized	0.4	$ 0.4	1.3	$ 1.3
Workers compensation liability	28		$ 28		$ 27.6
Workers' compensation accrual, discount rate (percent)			1.75%		3.00%
Accrued liabilities for employee healthcare benefits	$ 3.3		$ 3.3		$ 3.6
Shares available for award (shares)	481,282		481,282
Retained earnings	$ 193		$ 193		150.2
Long-term portion of operating lease liabilities	25.6		25.6		$ 0
Cumulative-effect adjustment							$ 10.1
Accrued salaries, wages and related expenses
Significant accounting policies
Accrued salaries, wages and related expenses	$ 6.4		$ 6.4
Accounting Standards Update 2016-02
Significant accounting policies
Operating lease assets						$ 29
Operating lease liabilities, current						4.1
Long-term portion of operating lease liabilities						27.4
Cumulative-effect adjustment						$ 0

Supplemental Balance Sheet In_3

Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Cash and Cash Equivalents
Cash and money market funds	$ 29.3	$ 22.9
Commercial paper	142.8	102.7
Total	172.1	125.6
Trade Receivables – Net
Trade receivables, gross	188.9	180.6
Allowance for doubtful receivables	(0.8)	(0.8)
Trade receivables – net	188.1	179.8
Inventories
Finished products	41.4	48
Work-in-process	80.5	85.6
Raw materials	63.7	75
Operating supplies	6.9	6.5
Total	192.5	215.1
Property, Plant and Equipment – Net
Land and improvements	21.4	21.4
Buildings and leasehold improvements	99.2	97
Machinery and equipment	797.9	755.6
Construction in progress	35.4	43.6
Property, plant and equipment – gross	953.9	917.6
Accumulated depreciation	(341.2)	(307.4)
Assets held for sale	1.6	1.6
Property, plant and equipment – net	614.3	611.8
Other Accrued Liabilities
Uncleared cash disbursements	3.7	4.8
Accrued income taxes and taxes payable	8	6.5
Accrued annual contribution to Salaried VEBA	0	2.1
Accrued interest	8.4	2.9
Accrued environmental	4.3	2.6
Other	25.7	25.1
Total	50.1	44
Long-Term Liabilities
Workers’ compensation accruals	26.9	24.6
Long-term environmental accrual	12.2	14.3
Other long-term liabilities	26.3	27.5
Total	65.4	66.4
Billed
Trade Receivables – Net
Trade receivables, gross	188.9	179.5
Unbilled
Trade Receivables – Net
Trade receivables, gross	$ 0	$ 1.1

Leases, Narrative (Details)

Leases, Narrative (Details)	9 Months Ended
	Sep. 30, 2019
Optional extension lease terms	20 years
Lease termination period	1 year
Minimum
Remaining lease terms	1 year
Maximum
Remaining lease terms	15 years

Leases, Weighted Averages (Deta

Leases, Weighted Averages (Details)	Sep. 30, 2019
Leases [Abstract]
Finance Lease, Weighted Average Remaining Lease Term	6 years
Operating Lease, Weighted Average Remaining Lease Term	10 years 6 months
Finance Lease, Weighted Average Discount Rate, Percent	4.50%
Operating Lease, Weighted Average Discount Rate, Percent	5.90%

Leases, Schedule of Lease Asset

Leases, Schedule of Lease Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease assets	$ 26.3	$ 0
Finance lease assets	6.8
Total lease assets	33.1
Operating lease liabilities, current	3.9
Finance lease liabilities, current	1.2
Operating lease liabilities, noncurrent	25.6	$ 0
Finance lease liabilities, noncurrent	5.6
Total lease liabilities	$ 36.3

Leases, Schedule of Lease Cost

Leases, Schedule of Lease Cost Classification (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease cost	$ 1.8	$ 5.6
Short-term lease cost	0.3	0.8
Amortization of leased assets	0.5	1.2
Interest on lease liabilities	0	0.2
Total lease cost	$ 2.6	$ 7.8

Leases, Maturity of Lease liabi

Leases, Maturity of Lease liability (Details) $ in Millions	Sep. 30, 2019USD ($)
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remainder of 2019	$ 1.3
2020	5.2
2021	4.4
2022	3.6
2023	3.4
2024	3.3
2025 and thereafter	18.9
Total minimum lease payments	40.1
Less: interest	(10.6)
Present value	29.5
Finance Lease, Liability, Payment, Due, Rolling Maturity [Abstract]
Remainder of 2019	0.4
2020	1.6
2021	1.4
2022	1.2
2023	1.1
2024	0.7
2025 and thereafter	1.4
Total minimum lease payments	7.8
Less: interest	(1)
Present value	$ 6.8

Leases, Schedule of Future Mini

Leases, Schedule of Future Minimum Rental Payments (Details) $ in Millions	Dec. 31, 2018USD ($)
Finance Leases
2019	$ 1.7
2020	1.4
2021	1.2
2022	1.1
2023	1
2024 and thereafter	1.8
Total minimum lease payments	8.2
Less: interest	(1.2)
Present value	7
Operating Leases
2019	6.1
2020	3.7
2021	2.8
2022	2.4
2023	2.2
2024 and thereafter	20.8
Total minimum lease payments	38
Assets recorded under finance leases	8.3
Accumulated amortization of assets recorded under finance lease	1.3
Accrued Liabilities
Operating Leases
Finance lease obligation included in Other accrued liabilities	1.4
Other Noncurrent Liabilities
Operating Leases
Finance lese obligation included in Long-term liabilities	$ 5.6

Employee Benefits Tables (Detai

Employee Benefits Tables (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure
Defined Contribution Plan, Cost	$ 1.7	$ 1.7	$ 7.3	$ 7.3
Deferred Compensation Arrangement with Individual, Compensation Expense	0.3	0.2	1.3	1.2
Multiemployer Plan, Contributions by Employer	1.3	1.2	3.7	3.5
Total other employee benefit plans	4.9	4.5	17.2	16.5
Postretirement Health Coverage | Salaried VEBA
Defined Benefit Plan Disclosure
Total net periodic postretirement benefit cost relating to Salaried VEBA	1.6	1.4	4.9	4.5
Salaried VEBA:
Interest cost	0.8	0.7	2.4	2.1
Expected return on plan assets	(0.7)	(0.8)	(2)	(2.2)
Amortization of prior service cost	1.4	1.3	4.2	4
Amortization of net actuarial loss	$ 0.1	$ 0.2	$ 0.3	$ 0.6

Employee Benefits Narrative (De

Employee Benefits Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Defined Benefit Plan Disclosure
Payment for Other Postretirement Benefits			$ 2.1	$ 15.7
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Defined Benefit Plan Disclosure
Fair value of deferred compensation assets			7.9		$ 10.5
Postretirement Health Coverage | Union VEBA
Defined Benefit Plan Disclosure
Maximum contribution threshold		$ 12.8
Postretirement Health Coverage | Salaried VEBA
Defined Benefit Plan Disclosure
Maximum contribution threshold			$ 2.9
Payment for Other Postretirement Benefits	$ 2.1

Derivatives, Hedging Programs_3

Derivatives, Hedging Programs and Other Financial Instruments, Narrative (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Collateral posted for net derivatives	$ 0							$ 0
Document Period End Date	Sep. 30, 2019
Maturity period of short-term investments	12 months
Customer Deposits, Current	$ 200,000							200,000
Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative net liability	$ 13,700,000							$ 12,600,000
Scenario, Forecast | Natural Gas
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage		77.00%	83.00%	83.00%	68.00%	68.00%	72.00%
Scenario, Forecast | Electricity
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage					46.00%	55.00%	54.00%

Derivatives, Hedging Programs_4

Derivatives, Hedging Programs and Other Financial Instruments, Material Derivative Positions (Details) mmlbs in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2019MMBTUeuroMWHmmlbs
Foreign Exchange Contract | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount | euro							3,189,200
Electricity | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount | MWH							394,680
Aluminum | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount							83.1
Aluminum | Designated as Hedging Instrument | Sales
Derivative [Line Items]
Derivative non-monetary notional amount							0.8
Midwest premium swap contracts | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount							57.6
Alloy Metal Hedge | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount							12.9
Natural Gas | Designated as Hedging Instrument | Purchase
Derivative [Line Items]
Derivative non-monetary notional amount | MMBTU							7,930,000
Scenario, Forecast | Electricity
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage				46.00%	55.00%	54.00%
Scenario, Forecast | Natural Gas
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage	77.00%	83.00%	83.00%	68.00%	68.00%	72.00%

Derivatives, Hedging Programs_5

Derivatives, Hedging Programs and Other Financial Instruments, Realized and Unrealized Gains (Losses) Table (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments Gain Loss [Line Items]
Cost of products sold, excluding depreciation and amortization and other items	$ 298.6	$ 323.3	$ 917.2	$ 983.4
Cost of Sales
Derivative Instruments Gain Loss [Line Items]
Cost of products sold, excluding depreciation and amortization and other items		323.3		983.4
Cost of Sales | Not Designated as Hedging Instrument
Derivative Instruments Gain Loss [Line Items]
Loss (gain) recognized in income related to cash flow hedges:	0.1	0	0.1	0
Cost of Sales | Designated as Hedging Instrument
Derivative Instruments Gain Loss [Line Items]
Loss (gain) recognized in income related to cash flow hedges:	5.4	3.1	14.3	(0.9)
Cost of Sales | Aluminum | Designated as Hedging Instrument
Derivative Instruments Gain Loss [Line Items]
Loss (gain) recognized in income related to cash flow hedges:	4.8	2.1	13.5	(1.2)
Cost of Sales | Alloy Metal Hedge | Designated as Hedging Instrument
Derivative Instruments Gain Loss [Line Items]
Loss (gain) recognized in income related to cash flow hedges:	0.5	1	0.7	0.4
Cost of Sales | Natural Gas | Designated as Hedging Instrument
Derivative Instruments Gain Loss [Line Items]
Loss (gain) recognized in income related to cash flow hedges:	0.1	0	0.1	(0.1)
Cost of Sales | Foreign Exchange Contract | Not Designated as Hedging Instrument
Derivative Instruments Gain Loss [Line Items]
Loss (gain) recognized in income related to cash flow hedges:	$ 0.1	$ 0	$ 0.1	$ 0

Derivatives, Hedging Programs_6

Derivatives, Hedging Programs and Other Financial Instruments, Fair Value Hierarchy Table (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	$ 2.2	$ 4.3
Derivative liability	(15.9)	(15.9)
Cash and cash equivalents	172.1	125.6
Total	197.4	162.3
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	29.3	22.9
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	2.2	4.3
Derivative liability	(15.9)	(15.9)
Derivative Assets (Liabilities), at Fair Value, Net	(13.7)	(11.6)
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Total	0	0
Designated as Hedging Instrument | Purchase
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability	(13.7)	(12.6)
Designated as Hedging Instrument | Purchase | Aluminum | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0.1
Derivative liability	(10.2)	(13.2)
Derivative Assets (Liabilities), at Fair Value, Net	(10.2)	(13.1)
Designated as Hedging Instrument | Purchase | Midwest premium swap contracts | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0.6	3.2
Derivative liability	(0.1)	(0.5)
Derivative Assets (Liabilities), at Fair Value, Net	0.5	2.7
Designated as Hedging Instrument | Purchase | Alloy Metal Hedge | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0
Derivative liability	(2)	(1.7)
Derivative Assets (Liabilities), at Fair Value, Net	(2)	(1.7)
Designated as Hedging Instrument | Purchase | Natural Gas | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0.2
Derivative liability	(2)	(0.5)
Derivative Assets (Liabilities), at Fair Value, Net	(2)	(0.3)
Designated as Hedging Instrument | Purchase | Electricity | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	1.5	0.7
Derivative liability	(1.5)	0
Derivative Assets (Liabilities), at Fair Value, Net	0	0.7
Designated as Hedging Instrument | Sales | Aluminum | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0.1	0.1
Derivative liability	0	0
Derivative Assets (Liabilities), at Fair Value, Net	0.1	0.1
Not Designated as Hedging Instrument | Purchase | Foreign Exchange Contract | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0
Derivative liability	(0.1)	0
Derivative Assets (Liabilities), at Fair Value, Net	(0.1)	0
Debt Securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	25.3	36.7
Debt Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Debt Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	168.1	139.4
Debt Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	$ 0	$ 0

Derivatives, Hedging Programs_7

Derivatives, Hedging Programs and Other Financial Instruments, Balance Sheet (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Cash and money market funds	$ 29.3	$ 22.9
Commercial paper	142.8	102.7
Short-term investments	$ 25.3	36.7
Document Period End Date	Sep. 30, 2019
Fair Value, Measurements, Recurring
Derivative [Line Items]
Cash and cash equivalents	$ 172.1	125.6
Derivative asset	2.2	4.3
Derivative liability	(15.9)	(15.9)
Fair Value, Measurements, Recurring | Other Current Liabilities
Derivative [Line Items]
Derivative liability	(12.8)	(13.2)
Fair Value, Measurements, Recurring | Other Noncurrent Liabilities
Derivative [Line Items]
Derivative liability	(3.1)	(2.7)
Fair Value, Measurements, Recurring | Other Current Assets
Derivative [Line Items]
Derivative asset	1.2	3.4
Fair Value, Measurements, Recurring | Other Assets
Derivative [Line Items]
Derivative asset	1	0.9
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Derivative [Line Items]
Cash and money market funds	29.3	22.9
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Derivative [Line Items]
Derivative asset	2.2	4.3
Derivative liability	(15.9)	(15.9)
Debt Securities | Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Derivative [Line Items]
Commercial paper	142.8	102.7
Short-term investments	$ 25.3	$ 36.7

Debt and Credit Facility, Narra

Debt and Credit Facility, Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	May 15, 2016
Senior Notes Due 2024 | Senior Notes
Debt Instrument
Debt principal amount						$ 375,000,000
Debt instrument contractual rate (percent)						5.875%
Debt issuance, percentage of principal amount						100.00%
Unamortized debt issuance cost	$ 3,900,000		$ 3,900,000
Interest expense	$ 5,700,000	$ 5,700,000	$ 17,100,000	$ 17,100,000
Effective interest rate (percent)	6.10%		6.10%
Fair value of outstanding debt	$ 386,800,000		$ 386,800,000		$ 369,900,000
Revolving Credit Facility | Line of Credit
Debt Instrument
Funding commitment provided	300,000,000		300,000,000
Available borrowing capacity under the Revolving Facility	300,000,000		300,000,000
Outstanding borrowings	0		0
Net borrowing availability	292,000,000		292,000,000
Revolving Credit Facility | Letter of Credit
Debt Instrument
Outstanding borrowings	$ 8,000,000		$ 8,000,000
Would have been | Revolving Credit Facility | Line of Credit
Debt Instrument
Applicable interest rate at period end (percent)	5.25%		5.25%

Commitments and Contingencies,

Commitments and Contingencies, Environmental (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Environmental Contingency
Environmental accrual	$ 16.5	$ 16.5
Expected period related to remediation expenditures for environmental contingencies period		30 years
Potential increase in environmental costs	$ 11.6	$ 11.6
Time period within which Companys recorded estimate of its obligation may change	12 months
Minimum
Environmental Contingency
Period for final feasibility study		6 months
Maximum
Environmental Contingency
Period for final feasibility study		12 months

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Estimated net mark-to-market loss before tax within next twelve months							$ 12.2
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 746.3	$ 747.9	$ 740.4	$ 761	$ 753.6	$ 746.3	740.4	$ 746.3
Other comprehensive income (loss), net of tax	(0.9)	(3.2)	9.7	(0.8)	6.4	(8.3)
Ending balance	751.4	746.3	747.9	762.5	761	753.6	751.4	762.5
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(33.4)		(35.6)	(36.1)		(38.5)	(35.6)	(38.5)
Less: income tax (expense) benefit	(0.3)			(0.4)			(1.1)	(1.1)
Net loss (gain) reclassified from AOCI to Net income	1.2			1.1			3.4	3.5
Other comprehensive income (loss), net of tax	1.2			1.1			3.4	3.5
Ending balance	(32.2)	(33.4)		(35)	(36.1)		(32.2)	(35)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification of unrealized gain upon sale of available for sale securities	0.1			0.2			0.3	0.6
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification of unrealized gain upon sale of available for sale securities	1.4			1.3			4.2	4
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	0		0.3	0.6		0.9	0.3	0.9
Unrealized gain (loss) on securities	1			1.3			2.7	3.6
Less: income tax benefit	(0.3)			(0.3)			(0.7)	(0.9)
Net unrealized loss on cash flow hedges	0.7			1			2	2.7
Reclassification of unrealized gain upon sale of available for sale securities	(0.9)			(1.6)			(3)	(4.3)
Less: income tax (expense) benefit	0.3			0.4			0.8	1.1
Net loss (gain) reclassified from AOCI to Net income	(0.6)			(1.2)			(2.2)	(3.2)
Other comprehensive income (loss), net of tax	0.1			(0.2)			(0.2)	(0.5)
Ending balance	0.1	0		0.4	0.6		0.1	0.4
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(8.8)		(13.4)	(3.5)		0.5	(13.4)	0.5
Unrealized gain (loss) on securities	(8.4)			(5.2)			(11.1)	(6.5)
Less: income tax benefit	2.1			1.2			2.7	1.6
Net unrealized loss on cash flow hedges	(6.3)			(4)			(8.4)	(4.9)
Reclassification of unrealized gain upon sale of available for sale securities	5.4			3			14.3	(1)
Less: income tax (expense) benefit	(1.3)			(0.7)			(3.5)	0.2
Net loss (gain) reclassified from AOCI to Net income	4.1			2.3			10.8	(0.8)
Other comprehensive income (loss), net of tax	(2.2)			(1.7)			2.4	(5.7)
Ending balance	(11)	(8.8)		(5.2)	(3.5)		(11)	(5.2)
Accumulated Other Comprehensive Loss (Other)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(0.1)		(0.1)	0		0	(0.1)	0
Other comprehensive income (loss), net of tax	0			0			0	0
Ending balance	(0.1)	(0.1)		0	0		(0.1)	0
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(42.3)	(39.1)	(48.8)	(39)	(45.4)	(36.7)	(48.8)	(36.7)
Other comprehensive income (loss), net of tax	(0.9)	(3.2)	9.7	(0.8)	6.4	(8.3)
Ending balance	$ (43.2)	$ (42.3)	$ (39.1)	$ (39.8)	$ (39)	$ (45.4)	$ (43.2)	$ (39.8)

Other (Expense) Income, Net (De

Other (Expense) Income, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Income and Expenses [Abstract]
Interest income	$ 0.2	$ 0.1	$ 0.5	$ 0.2
Net periodic postretirement benefit cost relating to Salaried VEBA	(1.6)	(1.4)	(4.9)	(4.5)
Realized gain on available for sale securities	0.9	1.6	3	4.3
Unrealized gain (loss) on equity securities	0.1	0.1	0.6	(0.3)
All other (expense) income, net	(0.4)	0.3	0.4	0.6
Other (expense) income, net	$ (0.8)	$ 0.7	$ (0.4)	$ 0.3

Income Tax Matters, Provision T

Income Tax Matters, Provision Table (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Tax Provision
Domestic	$ 8.5	$ 7.5	$ 24.7	$ 20.5
Foreign	0.2	0.7	1.1	1.4
Total	$ 8.7	$ 8.2	$ 25.8	$ 21.9

Income Tax Matters, Narrative (

Income Tax Matters, Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax provision	$ 8.7	$ 8.2	$ 25.8	$ 21.9
Effective tax rate (percent)	26.00%	27.00%	26.00%	24.00%
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Amount			$ (0.6)	$ (2)
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Percent			(1.00%)	(2.00%)
Effective tax rate reconciliation, increase (decrease) to the valuation allowance for certain state net operating losses		$ (0.4)	$ 0.6	$ (0.9)
Effective tax rate reconciliation, increase (decrease) to the valuation allowance for certain state net operating losses (percent)		(1.00%)	1.00%	(1.00%)
Effective Income Tax Rate Reconciliation Sequestration of AMT Credits Amount		$ 0.2		$ 0.6
Effective Income Tax Rate Reconciliation Sequestration of AMT Credits Percent		1.00%		1.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	$ 0.5	$ 0.6	$ 1.5	$ 1.7
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	2.00%	2.00%	2.00%	2.00%
Effective Income Tax Rate Reconciliation Advance Pricing Agreement, Amount		$ 0.3
Effective Income Tax Rate Reconciliation Advance Pricing Agreement, Percent		1.00%
Gross unrecognized tax benefits	$ 1.7		$ 1.7		$ 1.5
Gross unrecognized tax benefits that would impact effective tax rate	$ 0.6		$ 0.6		$ 0.4

Net Income Per Share and Stoc_3

Net Income Per Share and Stockholders' Equity, Calculation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net income	$ 25.4	$ 19.2	$ 28	$ 21.7	$ 20.7	$ 25.7	$ 72.6	$ 68.1
Denominator — Weighted-average common shares outstanding (in thousands):
Basic (shares)	15,956			16,573			16,042	16,654
Add: dilutive effect of non-vested common shares, restricted stock units, performance shares and stock options (shares)	169			210			193	228
Diluted (shares)	16,125			16,783			16,235	16,882
Net income per common share:
Basic (in dollars per share)	$ 1.59			$ 1.31			$ 4.52	$ 4.09
Earnings per common share, Diluted:
Diluted (in dollars per share)	$ 1.57			$ 1.29			$ 4.47	$ 4.03

Net Income Per Share and Stoc_4

Net Income Per Share and Stockholders' Equity, Anti Dilution Table (Details) shares in Thousands	Apr. 07, 2016	Sep. 30, 2019shares	Sep. 30, 2018shares	Sep. 30, 2019shares	Sep. 30, 2018shares
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		7	0	7	0
Series A Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Preferred Stock, Rights Conversion Ratio into Preferred Stock	1

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Interest paid	$ 10.6	$ 10.6
Supplemental disclosure of cash flow information:
Unpaid purchases of property and equipment	3.3	5.8
Stock repurchases not yet settled	0.3	0.4
Non-cash investing and financing activities:
Operating lease liabilities arising from obtaining operating lease assets	1.6
Cash paid for amounts included in the measurement of operating lease liabilities	2.8
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	0.9	0.3
Components of cash, cash equivalents and restricted cash:
Cash and cash equivalents	172.1	94.3	$ 125.6
Restricted cash included in Prepaid expenses and other current assets	0.3	0.3
Restricted cash included in Other assets	14.1	14.5
Total cash, cash equivalents and restricted cash presented on our Statements of Consolidated Cash Flows	$ 186.5	$ 109.1	$ 139.6	$ 64.3

Business, Product and Geograp_3

Business, Product and Geographical Area Information and Concentration of Risk, Net Sales by End Market Segment Applications (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net Sales:
Net sales	$ 374.9	$ 393.1	$ 1,145.4	$ 1,196.5
Transferred at Point in Time
Net Sales:
Net sales	115.9	127.8	378.7	425.2
Transferred over Time
Net Sales:
Net sales	259	265.3	766.7	771.3
Aero/HS products
Net Sales:
Net sales	198.9	185.7	586.8	540.9
Automotive Extrusions
Net Sales:
Net sales	47.5	56.1	146	183.9
GE products
Net Sales:
Net sales	117.1	133.9	375.3	425.1
Other products
Net Sales:
Net sales	$ 11.4	$ 17.4	$ 37.3	$ 46.6

Business, Product and Geograp_4

Business, Product and Geographical Area Information and Concentration of Risk, Income Taxes Paid by Geographical Area (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information
Income taxes paid	$ 0.5	$ 0.4	$ 3.6	$ 3.3
Domestic
Segment Reporting Information
Income taxes paid	0.1	0.4	2	1.3
Foreign
Segment Reporting Information
Income taxes paid	$ 0.4	$ 0	$ 1.6	$ 2

Business, Product and Geograp_5

Business, Product and Geographical Area Information and Concentration of Risk, Supply Information (Details) - Supplier Concentration Risk - Aluminum	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Top five major suppliers
Concentration Risk
Percentage of total primary aluminum supply (percent)	81.00%	83.00%	74.00%	82.00%
Largest supplier
Concentration Risk
Percentage of total primary aluminum supply (percent)	23.00%	33.00%	21.00%	36.00%
Second and third largest suppliers
Concentration Risk
Percentage of total primary aluminum supply (percent)	38.00%	36.00%	33.00%	32.00%

Business, Product and Geograp_6

Business, Product and Geographical Area Information and Concentration of Risk, Narrative (Details) - productionfacilities	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Segment Reporting Information
Percentage of employees covered by collective bargaining agreements	62.00%		62.00%
Percentage of employees covered by collective bargaining agreements expiring within one year	35.00%		35.00%
Domestic
Segment Reporting Information
Number of production facilities			12
Foreign
Segment Reporting Information
Number of production facilities			1
Customer Concentration Risk | Largest Customer | Sales Revenue, Net
Segment Reporting Information
Concentration percentages (percent)	24.00%	26.00%	25.00%	26.00%
Customer Concentration Risk | Largest Customer | Accounts Receivable
Segment Reporting Information
Concentration percentages (percent)			33.00%		31.00%
Customer Concentration Risk | Second Largest Customer | Sales Revenue, Net
Segment Reporting Information
Concentration percentages (percent)	19.00%	15.00%	16.00%	13.00%
Customer Concentration Risk | Second Largest Customer | Accounts Receivable
Segment Reporting Information
Concentration percentages (percent)			12.00%		11.00%

Condensed Guarantor and Non-G_3

Condensed Guarantor and Non-Guarantor Financial Information, Balance Sheets (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 172.1			$ 125.6	$ 94.3
Short-term investments	25.3			36.7
Receivables:
Trade receivables, net	188.1			179.8
Intercompany receivables	0			0
Other	26.1			25.6
Contract assets	46.1			54.9
Inventories	192.5			215.1
Prepaid expenses and other current assets	18.4			18.9
Total current assets	668.6			656.6
Investments in and advances to subsidiaries	0			0
Property, plant and equipment, net	614.3			611.8
Operating lease assets	26.3			0
Long-term intercompany loans receivable	0			0
Deferred tax assets, net	6.3			35.9
Intangible assets, net	30.3			32.4
Goodwill	44			44
Other assets	36.5			38.6
Total	1,426.3			1,419.3
Current liabilities:
Accounts payable	93.8			121.4
Intercompany loans payable	0			0
Accrued salaries, wages and related expenses	31.9			40.1
Other accrued liabilities	50.1			44
Total current liabilities	175.8			205.5
Long-term portion of operating lease liabilities	25.6			0
Net liabilities of Salaried VEBA	32.8			32.4
Deferred tax liabilities	4.2			4.2
Long-term intercompany loans payable	0			0
Long-term liabilities	65.4			66.4
Long-term debt	371.1			370.4
Total liabilities	674.9			678.9
Total stockholders' equity	751.4	$ 746.3	$ 747.9	740.4	$ 762.5	$ 761	$ 753.6	$ 746.3
Total	1,426.3			1,419.3
Consolidating Adjustments
Current assets:
Cash and cash equivalents	0			0
Short-term investments	0			0
Receivables:
Trade receivables, net	0			0
Intercompany receivables	(57.5)			(148.1)
Other	0			0
Contract assets	0			0
Inventories	0			0
Prepaid expenses and other current assets	0			0
Total current assets	(57.5)			(148.1)
Investments in and advances to subsidiaries	(1,177.3)			(1,069.8)
Property, plant and equipment, net	0			0
Operating lease assets	0
Long-term intercompany loans receivable	(17)			(9.8)
Deferred tax assets, net	3			3
Intangible assets, net	0			0
Goodwill	0			0
Other assets	0.1			0
Total	(1,248.7)			(1,224.7)
Current liabilities:
Accounts payable	0			0
Intercompany loans payable	(57.5)			(148.1)
Accrued salaries, wages and related expenses	0			0
Other accrued liabilities	(4.8)			(6.3)
Total current liabilities	(62.3)			(154.4)
Long-term portion of operating lease liabilities	0
Net liabilities of Salaried VEBA	0			0
Deferred tax liabilities	0			0
Long-term intercompany loans payable	(17)			(9.8)
Long-term liabilities	0			0
Long-term debt	0			0
Total liabilities	(79.3)			(164.2)
Total stockholders' equity	(1,169.4)			(1,060.5)
Total	(1,248.7)			(1,224.7)
Parent
Current assets:
Cash and cash equivalents	0			0
Short-term investments	0			0
Receivables:
Trade receivables, net	0			0
Intercompany receivables	50.6			143.7
Other	0			0
Contract assets	0			0
Inventories	0			0
Prepaid expenses and other current assets	0.3			0.1
Total current assets	50.9			143.8
Investments in and advances to subsidiaries	1,081.4			974.7
Property, plant and equipment, net	0			0
Operating lease assets	0
Long-term intercompany loans receivable	0			0
Deferred tax assets, net	0			0
Intangible assets, net	0			0
Goodwill	0			0
Other assets	0			0
Total	1,132.3			1,118.5
Current liabilities:
Accounts payable	1.5			4.9
Intercompany loans payable	0			0
Accrued salaries, wages and related expenses	0			0
Other accrued liabilities	8.3			2.8
Total current liabilities	9.8			7.7
Long-term portion of operating lease liabilities	0
Net liabilities of Salaried VEBA	0			0
Deferred tax liabilities	0			0
Long-term intercompany loans payable	0			0
Long-term liabilities	0			0
Long-term debt	371.1			370.4
Total liabilities	380.9			378.1
Total stockholders' equity	751.4			740.4
Total	1,132.3			1,118.5
Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	170.7			122.6
Short-term investments	25.3			36.7
Receivables:
Trade receivables, net	183.2			174
Intercompany receivables	1.4			0.1
Other	24.3			23.3
Contract assets	43.6			52
Inventories	183.1			203
Prepaid expenses and other current assets	17.7			18.4
Total current assets	649.3			630.1
Investments in and advances to subsidiaries	95.7			94.9
Property, plant and equipment, net	580.6			577.4
Operating lease assets	26.3
Long-term intercompany loans receivable	0			0
Deferred tax assets, net	3.3			32.9
Intangible assets, net	22.6			23.6
Goodwill	18.7			18.8
Other assets	36.2			38.6
Total	1,432.7			1,416.3
Current liabilities:
Accounts payable	86.7			109.6
Intercompany loans payable	56.1			148
Accrued salaries, wages and related expenses	30.3			38.3
Other accrued liabilities	46.1			46.7
Total current liabilities	219.2			342.6
Long-term portion of operating lease liabilities	25.6
Net liabilities of Salaried VEBA	32.8			32.4
Deferred tax liabilities	0			0
Long-term intercompany loans payable	17			9.8
Long-term liabilities	61.8			63.3
Long-term debt	0			0
Total liabilities	356.4			448.1
Total stockholders' equity	1,076.3			968.2
Total	1,432.7			1,416.3
Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	1.4			3
Short-term investments	0			0
Receivables:
Trade receivables, net	4.9			5.8
Intercompany receivables	5.5			4.3
Other	1.8			2.3
Contract assets	2.5			2.9
Inventories	9.4			12.1
Prepaid expenses and other current assets	0.4			0.4
Total current assets	25.9			30.8
Investments in and advances to subsidiaries	0.2			0.2
Property, plant and equipment, net	33.7			34.4
Operating lease assets	0
Long-term intercompany loans receivable	17			9.8
Deferred tax assets, net	0			0
Intangible assets, net	7.7			8.8
Goodwill	25.3			25.2
Other assets	0.2			0
Total	110			109.2
Current liabilities:
Accounts payable	5.6			6.9
Intercompany loans payable	1.4			0.1
Accrued salaries, wages and related expenses	1.6			1.8
Other accrued liabilities	0.5			0.8
Total current liabilities	9.1			9.6
Long-term portion of operating lease liabilities	0
Net liabilities of Salaried VEBA	0			0
Deferred tax liabilities	4.2			4.2
Long-term intercompany loans payable	0			0
Long-term liabilities	3.6			3.1
Long-term debt	0			0
Total liabilities	16.9			16.9
Total stockholders' equity	93.1			92.3
Total	$ 110			$ 109.2

Condensed Guarantor and Non-G_4

Condensed Guarantor and Non-Guarantor Financial Information, Comprehensive Income Statements (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Net sales	$ 374.9			$ 393.1			$ 1,145.4	$ 1,196.5
Costs and expenses:
Cost of products sold, excluding depreciation and amortization and other items	298.6			323.3			917.2	983.4
Depreciation and amortization	12.3			11			36.3	32.4
Selling, general, administrative, research and development	23.3			23.9			75.7	73.9
Other operating charges, net	0			0			0.1	0.1
Total costs and expenses	334.2			358.2			1,029.3	1,089.8
Operating income	40.7			34.9			116.1	106.7
Other (expense) income:
Interest expense	(5.8)			(5.7)			(17.3)	(17)
Other income, net	(0.8)			0.7			(0.4)	0.3
Income before income taxes	34.1			29.9			98.4	90
Income tax provision	(8.7)			(8.2)			(25.8)	(21.9)
Earnings in equity of subsidiaries	0			0			0	0
Net income	25.4	$ 19.2	$ 28	21.7	$ 20.7	$ 25.7	72.6	68.1
Comprehensive income	24.5			20.9			78.2	65.4
Consolidating Adjustments
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Net sales	(15.9)			(26.5)			(50.6)	(75.3)
Costs and expenses:
Cost of products sold, excluding depreciation and amortization and other items	(15.5)			(26.1)			(49.4)	(73)
Depreciation and amortization	0			0			0	0
Selling, general, administrative, research and development	(0.4)			(0.4)			(1.2)	(2.3)
Other operating charges, net							0	0
Total costs and expenses	(15.9)			(26.5)			(50.6)	(75.3)
Operating income	0			0			0	0
Other (expense) income:
Interest expense	0.1			0.1			0.3	0.4
Other income, net	(0.1)			(0.1)			(0.3)	(0.4)
Income before income taxes	0			0			0	0
Income tax provision	1.7			1.6			4.9	4.8
Earnings in equity of subsidiaries	(33.2)			(28.7)			(93.8)	(90.1)
Net income	(31.5)			(27.1)			(88.9)	(85.3)
Comprehensive income	(30.6)			(26.3)			(94.5)	(82.6)
Parent
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Net sales	0			0			0	0
Costs and expenses:
Cost of products sold, excluding depreciation and amortization and other items	0			0			0	0
Depreciation and amortization	0			0			0	0
Selling, general, administrative, research and development	1.5			1			4	3.7
Other operating charges, net							0	0
Total costs and expenses	1.5			1			4	3.7
Operating income	(1.5)			(1)			(4)	(3.7)
Other (expense) income:
Interest expense	(5.3)			(5.4)			(15.9)	(15.9)
Other income, net	0			0			0	0
Income before income taxes	(6.8)			(6.4)			(19.9)	(19.6)
Income tax provision	0			0			0	0
Earnings in equity of subsidiaries	32.2			28.1			92.5	87.7
Net income	25.4			21.7			72.6	68.1
Comprehensive income	24.5			20.9			78.2	65.4
Guarantor Subsidiaries
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Net sales	365.2			385.9			1,117.8	1,168.5
Costs and expenses:
Cost of products sold, excluding depreciation and amortization and other items	293.4			317.9			898.4	962.9
Depreciation and amortization	11.3			10.5			33.3	30.8
Selling, general, administrative, research and development	19.6			22.8			67.4	67.8
Other operating charges, net							0.1	0.1
Total costs and expenses	324.3			351.2			999.2	1,061.6
Operating income	40.9			34.7			118.6	106.9
Other (expense) income:
Interest expense	(0.6)			(0.4)			(1.7)	(1.5)
Other income, net	(0.8)			0.6			(0.6)	0.4
Income before income taxes	39.5			34.9			116.3	105.8
Income tax provision	(10)			(9)			(30)	(25.3)
Earnings in equity of subsidiaries	1			0.6			1.3	2.4
Net income	30.5			26.5			87.6	82.9
Comprehensive income	29.6			25.7			93.2	80.2
Non-Guarantor Subsidiaries
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Net sales	25.6			33.7			78.2	103.3
Costs and expenses:
Cost of products sold, excluding depreciation and amortization and other items	20.7			31.5			68.2	93.5
Depreciation and amortization	1			0.5			3	1.6
Selling, general, administrative, research and development	2.6			0.5			5.5	4.7
Other operating charges, net							0	0
Total costs and expenses	24.3			32.5			76.7	99.8
Operating income	1.3			1.2			1.5	3.5
Other (expense) income:
Interest expense	0			0			0	0
Other income, net	0.1			0.2			0.5	0.3
Income before income taxes	1.4			1.4			2	3.8
Income tax provision	(0.4)			(0.8)			(0.7)	(1.4)
Earnings in equity of subsidiaries	0			0			0	0
Net income	1			0.6			1.3	2.4
Comprehensive income	$ 1			$ 0.6			$ 1.3	$ 2.4

Condensed Guarantor and Non-G_5

Condensed Guarantor and Non-Guarantor Financial Information, Cash Flow Statements (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net cash (used in) provided by operating activities		$ 153.9	$ 112.5
Cash flows from investing activities
Capital expenditures		(40.7)	(53.1)
Purchase of available for sale securities		(56.3)	(111.9)
Purchase of equity securities		(0.7)	(0.9)
Proceeds from disposition of available for sale securities		68.2	208.7
Cash payment for acquisition of Imperial Machine & Tool Co., net of cash received		0	(43.3)
Proceeds from disposition of property, plant and equipment		0.2	0.6
Intercompany loans receivable		0	0
Net cash (used in) provided by investing activities	[1]	(29.3)	0.1
Cash flows from financing activities
Repayment of finance lease		(1.1)	(0.5)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(6.2)	(6.9)
Repurchase of common stock		(40.6)	(31.9)
Cash dividends paid to Parent		0	0
Cash dividends and dividend equivalents paid		(29.8)	(28.5)
Intercompany loans payable		0	0
Net cash used in financing activities	[1]	(77.7)	(67.8)
Net increase in cash, cash equivalents, and restricted cash during the period		46.9	44.8
Cash, cash equivalents and restricted cash at beginning of period		139.6	64.3
Cash, cash equivalents and restricted cash at end of period		186.5	109.1
Consolidating Adjustments
Cash flows from operating activities:
Net cash (used in) provided by operating activities		(0.5)	(100)
Cash flows from investing activities
Capital expenditures		0	0
Purchase of available for sale securities		0	0
Purchase of equity securities		0	0
Proceeds from disposition of available for sale securities		0	0
Cash payment for acquisition of Imperial Machine & Tool Co., net of cash received			0
Proceeds from disposition of property, plant and equipment		0	0
Intercompany loans receivable		(83.4)	21.7
Net cash (used in) provided by investing activities		(83.4)	21.7
Cash flows from financing activities
Repayment of finance lease		0	0
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		0	0
Repurchase of common stock		0	0
Cash dividends paid to Parent		0.5	100
Cash dividends and dividend equivalents paid		0	0
Intercompany loans payable		83.4	(21.7)
Net cash used in financing activities		83.9	78.3
Net increase in cash, cash equivalents, and restricted cash during the period		0	0
Cash, cash equivalents and restricted cash at beginning of period		0	0
Cash, cash equivalents and restricted cash at end of period		0	0
Parent
Cash flows from operating activities:
Net cash (used in) provided by operating activities		(16.5)	87.5
Cash flows from investing activities
Capital expenditures		0	0
Purchase of available for sale securities		0	0
Purchase of equity securities		0	0
Proceeds from disposition of available for sale securities		0	0
Cash payment for acquisition of Imperial Machine & Tool Co., net of cash received			0
Proceeds from disposition of property, plant and equipment		0	0
Intercompany loans receivable		93.1	(20.2)
Net cash (used in) provided by investing activities		93.1	(20.2)
Cash flows from financing activities
Repayment of finance lease		0	0
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(6.2)	(6.9)
Repurchase of common stock		(40.6)	(31.9)
Cash dividends paid to Parent		0	0
Cash dividends and dividend equivalents paid		(29.8)	(28.5)
Intercompany loans payable		0	0
Net cash used in financing activities		(76.6)	(67.3)
Net increase in cash, cash equivalents, and restricted cash during the period		0	0
Cash, cash equivalents and restricted cash at beginning of period		0	0
Cash, cash equivalents and restricted cash at end of period		0	0
Guarantor Subsidiaries
Cash flows from operating activities:
Net cash (used in) provided by operating activities		163.6	78.5
Cash flows from investing activities
Capital expenditures		(39.4)	(51.9)
Purchase of available for sale securities		(56.3)	(111.9)
Purchase of equity securities		(0.7)	(0.9)
Proceeds from disposition of available for sale securities		68.2	208.7
Cash payment for acquisition of Imperial Machine & Tool Co., net of cash received			0
Proceeds from disposition of property, plant and equipment		0.2	0.6
Intercompany loans receivable		(1.3)	(0.4)
Net cash (used in) provided by investing activities		(29.3)	44.2
Cash flows from financing activities
Repayment of finance lease		(1.1)	(0.5)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		0	0
Repurchase of common stock		0	0
Cash dividends paid to Parent		0	(100)
Cash dividends and dividend equivalents paid		0	0
Intercompany loans payable		(84.7)	21.4
Net cash used in financing activities		(85.8)	(79.1)
Net increase in cash, cash equivalents, and restricted cash during the period		48.5	43.6
Cash, cash equivalents and restricted cash at beginning of period		136.3	61.3
Cash, cash equivalents and restricted cash at end of period		184.8	104.9
Non-Guarantor Subsidiaries
Cash flows from operating activities:
Net cash (used in) provided by operating activities		7.3	46.5
Cash flows from investing activities
Capital expenditures		(1.3)	(1.2)
Purchase of available for sale securities		0	0
Purchase of equity securities		0	0
Proceeds from disposition of available for sale securities		0	0
Cash payment for acquisition of Imperial Machine & Tool Co., net of cash received			(43.3)
Proceeds from disposition of property, plant and equipment		0	0
Intercompany loans receivable		(8.4)	(1.1)
Net cash (used in) provided by investing activities		(9.7)	(45.6)
Cash flows from financing activities
Repayment of finance lease		0	0
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		0	0
Repurchase of common stock		0	0
Cash dividends paid to Parent		(0.5)	0
Cash dividends and dividend equivalents paid		0	0
Intercompany loans payable		1.3	0.3
Net cash used in financing activities		0.8	0.3
Net increase in cash, cash equivalents, and restricted cash during the period		(1.6)	1.2
Cash, cash equivalents and restricted cash at beginning of period		3.3	3
Cash, cash equivalents and restricted cash at end of period		$ 1.7	$ 4.2
[1]	See Note 12 for supplemental cash flow information.

Condensed Guarantor and Non-G_6

Condensed Guarantor and Non-Guarantor Financial Information, Narrative (Details) - USD ($)	Sep. 30, 2019	May 15, 2016
Condensed Financial Statements, Captions
Ownership interest by parent	100.00%
Senior Notes Due 2024 | Senior Notes
Condensed Financial Statements, Captions
Debt principal amount		$ 375,000,000

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 15, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Subsequent Event [Line Items]
Cash dividends declared (in dollars per share)		$ 0.60	$ 0.60	$ 0.55	$ 0.55	$ 0.55
Subsequent Event
Subsequent Event [Line Items]
Cash dividends declared (in dollars per share)	$ 0.60
Cash dividends declared	$ 9.6