Stock Based Compensation (Awards of Restricted Stock) (Details) - Restricted Stock [Member]	6 Months Ended
Jun. 30, 2021 $ / shares shares
Ratably Over Period [Member] \| 2/18/2021 \| Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Granted \| shares	49,550
Grant Date Fair Value Per Share \| $ / shares	$ 81.84
Vesting Period	Ratably over 5 years from grant date
Immediate Vest on grant date [Member] \| 5/25/2021 \| Two Thousand Eighteen Nonemployee Director Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Granted \| shares	7,680
Grant Date Fair Value Per Share \| $ / shares	$ 78.18
Vesting Period	Shares vested immediately

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).

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

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

Net number of non-option equity instruments granted to participants.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Description of terms of award under share-based payment arrangement.

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