Employee Benefit Plans (Schedule of Restricted Stock Plan) (Details) - 2008 Restricted Stock Plan [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Shares
Balance	97	125	132
Granted	16	18	22
Vested	(27)	(28)	(27)
Forfeited		(18)	(2)
Amortization of Compensation Expense
Balance	86	97	125
Unearned compensation
Balance	$ 1,706	$ 1,638	$ 1,785
Granted	982	975	827
Vested
Forfeited			(18)
Amortization of Compensation Expense	(851)	(907)	(956)
Balance	$ 1,837	$ 1,706	$ 1,638
Weighted Average Grant Price
Granted	$ 60.12	$ 55.99	$ 36.53

Amortization of Compensation Expense - Unearned compensation

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- Definition

Amount of forfeitures of unearned compensation.

+ References

No definition available.

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The grant-date value of unearned compensation.

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No definition available.

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The weighted average grant-date fair value of unearned compensation granted during the reporting period.

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No definition available.

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Unearned Compensation [Abstract].

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The grant-date value of unearned compensation for awards vested.

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No definition available.

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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

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

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- Definition

Number of non-option equity instruments exercised by participants.

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Number of shares under non-option equity instrument agreements that were cancelled as a result of occurrence of a terminating event.

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

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Other increase (decrease) in number of shares reserved for issuance under non-option equity instrument agreements that is not separately disclosed.

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- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ 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
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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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