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Percentage of incentive compensation to acquire shares maximum.

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Amount of cash outflow for realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

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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).

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

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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.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of shares issued under share-based payment arrangement.

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Intrinsic value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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Intrinsic value of vested award under share-based payment arrangement. Excludes share and unit options.

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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.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended				240 Months Ended	300 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of incentive compensation to acquire shares, maximum	50.00%
Percentage of discount rate to market value on the incentive compensation	20.00%
Company normal retirement age	62 years
Common stock price	$ 283.97				$ 283.97	$ 283.97
Aggregate intrinsic values of options exercised	$ 3.3	$ 21.6	$ 12.4
Aggregate intrinsic values for options outstanding	4.8				$ 4.8	$ 4.8
Aggregate intrinsic values for options exercisable	$ 4.8				$ 4.8	$ 4.8
Awards available for grant	600,000				600,000	600,000
Additional shares issuance under the plan				800,000
Options granted in 2015 and 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock options expiration date	10 years
Options granted prior to 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock options expiration date	8 years
Incentive Compensation Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value of stock awards, granted	$ 258.67	$ 192.27	$ 212.12
Aggregate intrinsic values for stock awards	$ 4.5				$ 4.5	$ 4.5
Common stock price	$ 283.97				$ 283.97	$ 283.97
Aggregate intrinsic values of stock awards, distributed	$ 1.7	$ 1.5	$ 1.7
Awards granted	21,082
Restricted Stock - Service Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value of stock awards, granted	$ 222.39	$ 196.91	$ 211.03
Awards granted	92,472
Restricted Stock - Performance Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value of stock awards, granted	$ 266.97	$ 192.27	$ 212.12
Awards granted	38,272
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic values for stock awards	$ 92.4				$ 92.4	$ 92.4
Aggregate intrinsic values of stock awards, distributed	35.2	$ 49.8	$ 23.0
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefits for stock options exercised	$ 0.1	$ 2.0	$ 1.7
Legacy TXI plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards available for grant	0				0	0
Shareholder Value Achievement Plan (1996)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance							300,000
Common stock issued under the plan						42,025
Awards granted					0
Directors' Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	300,000				300,000	300,000
Common stock issued under the plan	3,043	2,756	3,105