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Segment Information - Additional Information (Detail)	6 Months Ended
	Sep. 30, 2017 Location Facility Terminal Plant Segment Center JointVentures
Segment Reporting Information [Line Items]
Number of operating business segments | Segment	5
Cement plant locations | Location	7
Slag grinding facility | Facility	1
Cement distribution terminals | Terminal	17
Gypsum wallboard plants | Plant	5
Readymix concrete batch plant | Plant	17
Aggregates processing plant | Plant	4
Number of frac sand processing facilities | Facility	2
Number of frac sand drying facilities | Facility	3
Number of frac sand trans-load locations | Location	6
Number of frac sand distribution centers | Center	11
Proportionate consolidation of share of Joint Venture's revenues and operating earnings	50.00%
Cement [Member]
Segment Reporting Information [Line Items]
Number of Joint Venture | JointVentures	1

X

- Definition

Aggregates processing plant.

+ References

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X

- Definition

Cement distribution terminals.

+ References

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- Definition

Cement plant locations.

+ References

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- Definition

Gypsum wallboard plants.

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- Definition

Number of frac sand distribution centers.

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- Definition

Number of frac sand drying facilities.

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- Definition

Number of frac sand processing facilities.

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- Definition

Number of frac sand trans-load locations.

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- Definition

Number of joint ventures.

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- Definition

Readymix plant.

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- Definition

Segment reporting information proportionate consolidation of joint ventures revenues and operating earnings.

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- Definition

Slag grinding facility.

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X

- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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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.

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