Number of Nonvested Target Units, Vested or expected to vest at December 31, 2015

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Award Contractual Life

+ References

No definition available.

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- Definition

Share-based compensation arrangement by share-based payment award, equity instruments other than options, exercised and vested in period, weighted average grant date fair value.

+ References

No definition available.

+ Details

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- Definition

Stock Options, Number of stock incentive plans

+ References

No definition available.

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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=96867065&loc=d3e5070-113901

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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=96867065&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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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=96867065&loc=d3e5070-113901

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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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Stock-Based Compensation Plans (Narrative) (Details)	1 Months Ended	12 Months Ended
Stock-Based Compensation Plans (Narrative) (Details)	May 31, 2016 shares	Dec. 31, 2017 item $ / shares shares	Dec. 31, 2016 shares	Dec. 31, 2015 shares	Mar. 31, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock incentive plans \| item		2
Number of shares authorized		3,800,000
Options granted		330,550	505,775	422,750
Perfromance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of stock granted		27,622
Shares vesting period, years		3 years
Per-share weighted averaged grant-date fair value of stock awards vested \| $ / shares		$ 99.50
Perfromance Stock Units [Member] \| Scenario, Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested share units that will be converted					37,466
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting period, years		3 years
Shares contractual life		5 years
Stock Options [Member] \| Prior to Year 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares contractual life		10 years
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting period, years		3 years
Performance Based TSR [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of stock granted		7,304	9,541	10,761
Performance Based EPS [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of stock granted		7,304	9,541	10,761
Outside Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted	3,762