Common stock number of votes.

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- Definition

Common stock number of votes in all matters except election of directors.

+ References

No definition available.

+ Details

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- Definition

Common stock number of votes in election of directors.

+ References

No definition available.

+ Details

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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

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- Definition

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.

+ References

No definition available.

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- Definition

Number of additional shares authorized for issuance under an established share-based compensation plan.

+ References

No definition available.

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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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

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- Definition

Number of shares that have been repurchased during the period and are being held in treasury.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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Stockholders' Equity - Additional Information (Detail)	12 Months Ended
Stockholders' Equity - Additional Information (Detail)	Dec. 31, 2016 Vote $ / shares shares	Dec. 31, 2015 $ / shares shares	Dec. 31, 2014 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Treasury stock purchases	0	0	0
Shares available for purchase	678,000
Common Stock Dividend declared by directors \| $ / shares	$ 0.05	$ 0.05	$ 0.05
2013 Director Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for award	173,000
Non-Employee \| 2013 Director Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares authorized to be issued under the plan	200,000
Class A Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, vote per share \| Vote	1
Class B Common Stock \| NL Industries
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, vote per share \| Vote	1
Common stock, vote per share \| Vote	10