Segment Information - Segment Breakdown of Goodwill (Detail) - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026
Segment Reporting Information [Line Items]
Goodwill	$ 470,673	$ 470,673
Cement [Member]
Segment Reporting Information [Line Items]
Goodwill	227,639	227,639
Concrete and Aggregates [Member]
Segment Reporting Information [Line Items]
Goodwill	118,878	118,878
Gypsum Wallboard [Member]
Segment Reporting Information [Line Items]
Goodwill	116,618	116,618
Recycled Paperboard [Member]
Segment Reporting Information [Line Items]
Goodwill	$ 7,538	$ 7,538

Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized.

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+ Details

- 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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+ Details