Stock-Based Compensation - Remaining Shares Authorized to Be Granted for Options, Restricted Stock Awards and Performance Stock Awards (Details) - shares	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Options, RSUs or PSUs
Number of Shares
Balance (in shares)	299,242	407,619	479,953
Balance (in shares)	222,981	299,242	407,619
Restricted Stock Units (RSUs)
Number of Shares
Balance (in shares)	115,466	76,746	75,707
Grants (in shares)	(26,818)	(71,716)	(38,806)
Forfeitures (in shares)	1,653	9,461	1,515
Balance (in shares)	114,846	115,466	76,746
Performance Stock Awards
Number of Shares
Balance (in shares)	136,271	121,656	168,453
Grants (in shares)	(53,685)	(72,273)	(40,722)
Non-vesting (in shares)	0	12,689	0
PSUs added by performance factor	0	(3,688)	0
Forfeitures (in shares)	2,589	17,150	5,679
Balance (in shares)	149,911	136,271	121,656

The number of equity-based awards cancelled in the period.

No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Increase From Performance Factor

+ References

No definition available.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited 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)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=120381028&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

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

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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=120381028&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.

+ Details

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