Share-Based Transactions - Narrative (Details) - $ / shares		6 Months Ended
Feb. 26, 2018	Jun. 30, 2018
Equity award granted with sales restrictions [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, sale restrictions expiration period		3 years
Restricted stock units (RSUs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares awarded	94,758
Measurement date fair value	$ 100.55
Share-based compensation arrangement by share-based payment award, award vesting period	3 years
Performance share units (PSUs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares awarded	30,579
Measurement date fair value	$ 100.55
Share-based compensation arrangement by share-based payment award, award vesting period	3 years
Performance share units (PSUs) [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of PSUs vested during the period	45,868
Performance share units (PSUs) [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of PSUs vested during the period	0

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.

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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).

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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).

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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-Publisher FASB
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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.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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