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Employee Incentive Plans, Long term Incentive Plans (Details) - USD ($) $ / shares in Units, $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2015 | Sep. 30, 2014 | Sep. 30, 2015 | Sep. 30, 2014 | Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Number of common shares authorized for issuance under Equity Incentive Plan | 2,722,222 |  | 2,722,222 |  |
Number of common shares available for additional awards under Equity Incentive Plan | 707,090 |  | 707,090 |  |
Non-cash compensation expense | $ 2.2 | $ 0.9 | $ 6.8 | $ 5.2 |
Stock Options |  |  |  |  |
Fully-vested options outstanding | 16,645 |  | 16,645 |  | 16,645
Exercise price of options to purchase common stock | $ 80.01 |  | $ 80.01 |  | $ 80.01
Remaining contractual life of options outstanding |  |  | 1 year 6 months |  | 2 years 3 months
Grant date fair value of options outstanding |  |  | $ 39.90 |  | $ 39.90
Stock options granted |  |  | 0 |  |
Stock options forfeited |  |  | 0 |  |
Stock options exercised |  |  | 0 |  |
Fabricated Products |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Non-cash compensation expense | $ 0.8 | 0.5 | $ 2.4 | 2.6 |
All Other |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Non-cash compensation expense | $ 1.4 | 0.4 | $ 4.4 | 2.6 |
Non-vested common shares |  |  |  |  |
Summary of Activity |  |  |  |  |
Outstanding at December 31, 2014 |  |  | 158,770 |  |
Weighted-Average Grant-Date Fair Value per Share |  |  | $ 59.88 |  |
Granted, shares |  |  | 62,285 |  |
Granted, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 72.09 |  |
Vested, shares |  |  | (58,241) |  |
Vested, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 52.76 |  |
Forfeited, shares |  |  | (793) |  |
Forfeited, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 67.83 |  |
Canceled, Shares |  |  | 0 |  |
Canceled, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 0 |  |
Outstanding at September 30, 2015 | 162,021 |  | 162,021 |  | 158,770
Weighted-Average Grant-Date Fair Value per Share | $ 67.09 |  | $ 67.09 |  | $ 59.88
Restricted stock units (RSUs) |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Number of common shares received by the employee on vesting of restricted stock unit |  |  | 1 |  |
Summary of Activity |  |  |  |  |
Outstanding at December 31, 2014 |  |  | 5,357 |  |
Weighted-Average Grant-Date Fair Value per Share |  |  | $ 59.71 |  |
Granted, shares |  |  | 2,325 |  |
Granted, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 69.83 |  |
Vested, shares |  |  | (2,161) |  |
Vested, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 52.91 |  |
Forfeited, shares |  |  | 0 |  |
Forfeited, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 0 |  |
Canceled, Shares |  |  | 0 |  |
Canceled, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 0 |  |
Outstanding at September 30, 2015 | 5,521 |  | 5,521 |  | 5,357
Weighted-Average Grant-Date Fair Value per Share | $ 66.64 |  | $ 66.64 |  | $ 59.71
Non-vested common shares and restricted stock units |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Non-cash compensation expense | $ 1.1 | 0.5 | $ 3.3 | 2.8 |
Unrecognized gross compensation costs (in millions of dollars) | 6.9 |  | $ 6.9 |  |
Expected period (in years) over which the remaining gross compensation costs will be recognized |  |  | 2 years |  |
EVA-Based Performance Shares |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Performance award vesting period, years |  |  | 3 years |  |
Non-cash compensation expense | 0.1 | 0.0 | $ 0.8 | 1.0 |
Unrecognized gross compensation costs (in millions of dollars) | $ 0.6 |  | $ 0.6 |  |
Expected period (in years) over which the remaining gross compensation costs will be recognized |  |  | 6 months |  |
Summary of Activity |  |  |  |  |
Outstanding at December 31, 2014 |  |  | 353,576 |  |
Weighted-Average Grant-Date Fair Value per Share |  |  | $ 50.35 |  |
Granted, shares |  |  | 0 |  |
Granted, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 0.00 |  |
Vested, shares |  |  | (48,648) |  |
Vested, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 44.48 |  |
Forfeited, shares |  |  | (432) |  |
Forfeited, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 57.54 |  |
Canceled, Shares |  |  | (146,016) |  |
Canceled, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 44.48 |  |
Outstanding at September 30, 2015 | 158,480 |  | 158,480 |  | 353,576
Weighted-Average Grant-Date Fair Value per Share | $ 57.75 |  | $ 57.75 |  | $ 50.35
TSR-Based Performance Shares |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Non-cash compensation expense | $ 1.0 | $ 0.4 | $ 2.7 | $ 1.4 |
Unrecognized gross compensation costs (in millions of dollars) | $ 8.8 |  | $ 8.8 |  |
Expected period (in years) over which the remaining gross compensation costs will be recognized |  |  | 2 years 1 month |  |
Summary of Activity |  |  |  |  |
Outstanding at December 31, 2014 |  |  | 150,223 |  |
Weighted-Average Grant-Date Fair Value per Share |  |  | $ 83.18 |  |
Granted, shares |  |  | 150,424 |  |
Granted, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 95.68 |  |
Vested, shares |  |  | 0 |  |
Vested, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 0 |  |
Forfeited, shares |  |  | (770) |  |
Forfeited, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 89.12 |  |
Canceled, Shares |  |  | 0 |  |
Canceled, Weighted-Average Grant-Date Fair Value per Share |  |  | $ 0 |  |
Outstanding at September 30, 2015 | 299,877 |  | 299,877 |  | 150,223
Weighted-Average Grant-Date Fair Value per Share | $ 89.43 |  | $ 89.43 |  | $ 83.18
Minimum |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Performance award vesting period, years | 1 year |  |  |  |
Minimum | EVA-Based Performance Shares |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 0.00% |  |  |  |
Minimum | TSR-Based Performance Shares |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 0.00% |  |  |  |
Maximum |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Performance award vesting period, years | 3 years |  |  |  |
Maximum | EVA-Based Performance Shares |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 200.00% |  |  |  |
Maximum | TSR-Based Performance Shares |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 200.00% |  |  |  |

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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section F + Details
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Gross number of share options (or share units) granted during the period. + References No definition available. + Details
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Percentage of vesting of share-based compensation awards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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