Stock-Based Compensation - Narrative (Details) - shares	12 Months Ended
Dec. 31, 2020	Dec. 31, 2013
Members of the Board
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	2 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share initially made available for awards (in shares)		830,925
Additional shares added to the plan (in shares)		700,000
Share available for issuance of future awards (in shares)	408,734
Expiration period	10 years

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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 (a)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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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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- Definition

Number of additional shares authorized for issuance under share-based payment arrangement.

+ References

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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