Stock Plans - Summary of Restricted Stock and Unit Activity (Details)	6 Months Ended
Jun. 30, 2020 $ / shares shares
Performance Shares
Shares
Unvested, beginning balance (in shares) \| shares	238,035
Granted (in shares) \| shares	64,791
Vested (in shares) \| shares	(132,036)
Forfeited (in shares) \| shares	(3,698)
Unvested, ending balance (in shares) \| shares	200,591
Weighted Average Exercise Price (dollars per share)
Unvested, beginning balance (dollars per share) \| $ / shares	$ 85.39
Granted (dollars per share) \| $ / shares	127.36
Vested (dollars per share) \| $ / shares	73.00
Forfeited (dollars per share) \| $ / shares	120.69
Unvested, ending Balance (dollars per share) \| $ / shares	$ 104.28
Restricted Stock Activity
Shares
Unvested, beginning balance (in shares) \| shares	172,701
Granted (in shares) \| shares	47,355
Vested (in shares) \| shares	(59,464)
Forfeited (in shares) \| shares	(3,065)
Unvested, ending balance (in shares) \| shares	157,527
Weighted Average Exercise Price (dollars per share)
Unvested, beginning balance (dollars per share) \| $ / shares	$ 90.38
Granted (dollars per share) \| $ / shares	122.65
Vested (dollars per share) \| $ / shares	81.30
Forfeited (dollars per share) \| $ / shares	97.28
Unvested, ending Balance (dollars per share) \| $ / shares	$ 103.38

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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=116856206&loc=d3e5070-113901

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(3)
-URI http://asc.fasb.org/extlink&oid=116856206&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

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-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=116856206&loc=d3e5070-113901

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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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-Publisher FASB
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-Topic 718
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-Paragraph 2
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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

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-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.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 2
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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

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

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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