Share-Based Compensation Plans - Restricted Stock Awards, Activity (Details) - Restricted Stock shares in Thousands	12 Months Ended
Dec. 31, 2018 $ / shares shares
Time-Vested
Shares
Unvested stock outstanding at January 1 (in shares) \| shares	433
Granted (in shares) \| shares	173
Vested (in shares) \| shares	(89)
Forfeited (in shares) \| shares	(29)
Unvested stock outstanding at December 31 (in shares) \| shares	488
Weighted- Average Grant Date Fair Value
Nonvested stock outstanding at January 1 (in dollars per share) \| $ / shares	$ 65.91
Granted (in dollars per share) \| $ / shares	74.05
Vested (in dollars per share) \| $ / shares	79.02
Forfeited (in dollars per share) \| $ / shares	70.92
Nonvested stock outstanding at December 31 (in dollars per share) \| $ / shares	$ 66.11
Market-Based
Shares
Unvested stock outstanding at January 1 (in shares) \| shares	92
Granted (in shares) \| shares	0
Vested (in shares) \| shares	(7)
Forfeited (in shares) \| shares	(17)
Unvested stock outstanding at December 31 (in shares) \| shares	68
Weighted- Average Grant Date Fair Value
Nonvested stock outstanding at January 1 (in dollars per share) \| $ / shares	$ 68.26
Granted (in dollars per share) \| $ / shares	0.00
Vested (in dollars per share) \| $ / shares	89.40
Forfeited (in dollars per share) \| $ / shares	75.14
Nonvested stock outstanding at December 31 (in dollars per share) \| $ / shares	$ 64.26
Performance-Based
Shares
Unvested stock outstanding at January 1 (in shares) \| shares	94
Granted (in shares) \| shares	200
Vested (in shares) \| shares	(20)
Forfeited (in shares) \| shares	(45)
Unvested stock outstanding at December 31 (in shares) \| shares	229
Weighted- Average Grant Date Fair Value
Nonvested stock outstanding at January 1 (in dollars per share) \| $ / shares	$ 78.91
Granted (in dollars per share) \| $ / shares	73.88
Vested (in dollars per share) \| $ / shares	78.58
Forfeited (in dollars per share) \| $ / shares	76.02
Nonvested stock outstanding at December 31 (in dollars per share) \| $ / shares	$ 73.41

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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=109197908&loc=d3e5070-113901

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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

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-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=109197908&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

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-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=109197908&loc=d3e5070-113901

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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
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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://fasb.org/us-gaap/role/ref/legacyRef
-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=109197908&loc=d3e5070-113901

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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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://fasb.org/us-gaap/role/ref/legacyRef
-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=109197908&loc=d3e5070-113901

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+ References

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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://fasb.org/us-gaap/role/ref/legacyRef
-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=109197908&loc=d3e5070-113901

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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

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-Publisher FASB
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-SubTopic 10
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