Stock Compensation Plans - SSAR's and Stock Option Activity (Detail) - SSAR's and Stock Options [Member] - $ / shares shares in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Shares Subject to SSARs/Options
Beginning balance (in shares)	12
Granted (in shares)	6
Exercised (in shares)	(3)
Cancelled (in shares)	0
Ending balance (in shares)	15	12
Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 117.21
Granted (in dollars per share)	137.82
Exercised (in dollars per share)	60.39
Cancelled (in dollars per share)	0
Ending balance (in dollars per share)	$ 138.73	$ 117.21
SSARs/ Options Exercisable (in shares)	1	4

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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- Definition

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ References

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Weighted average price of options that were either forfeited or expired.

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- Definition

Net number of share options (or share units) granted during the period.

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- Definition

Number of options outstanding, including both vested and non-vested options.

+ 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
-URI http://asc.fasb.org/extlink&oid=116856206&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.

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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- Definition

Weighted average price at which option holders acquired shares when converting their stock options into shares.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

+ References

No definition available.

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- Definition

Number of share options (or share units) exercised during the current period.

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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
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