Share-Based Compensation and Benefit Plans (Restricted Stock Activity) (Details) - Restricted stock [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-Based Compensation and Benefit Plans
Compensation expense for share-based compensation	$ 1,370	$ 1,628	$ 1,293
Income tax benefit from compensation expense for share-based compensation	340	621	483
Total fair value of shares vested, at vest date	$ 1,230	$ 1,202	$ 2,384
Weighted-average grant-date fair value of shares issued during the period in compensation and benefit plans other than stock options	$ 263.89	$ 253.78	$ 264.24
Performance shares [Member]
Share-Based Compensation and Benefit Plans
Shares awarded or issued under employee benefit plans, shares	5	4	4

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.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 2
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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
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-Paragraph 2
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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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-Paragraph 2
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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.

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No definition available.

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- Definition

Number of shares issued during the period to an employee benefit plan, such as a defined contribution or defined benefit plan.

+ References

No definition available.

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