Business Segments - Financial Information Related to Operations by Segment (Detail) $ in Thousands	12 Months Ended
	Mar. 31, 2024 USD ($) kt	Mar. 31, 2023 USD ($) kt	Mar. 31, 2022 USD ($) kt
Segment Reporting Information [Line Items]
Revenue	$ 2,259,297	$ 2,148,069	$ 1,861,522
Operating Earnings	716,902	674,740	552,102
Corporate General and Administrative Expense	(59,795)	(53,630)	(46,801)
Loss on Early Retirement of Senior Notes	0	0	(8,407)
Other Nonoperating Income (Loss)	3,087	2,654	9,073
Earnings Before Interest and Income Taxes	660,194	623,764	505,967
Interest Expense, net	(42,257)	(35,171)	(30,873)
Earnings Before Income Taxes	617,937	588,593	475,094
Capital Expenditures	120,305	110,143	74,121
Depreciation, Depletion, and Amortization	149,832	138,554	128,811
Segment Assets	2,947,019	2,781,002	2,579,652
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	2,502,687	2,387,337	2,070,422
Depreciation, Depletion, and Amortization	149,832	138,554	128,811
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	(130,654)	(125,750)	(105,001)
Revenue	130,654	125,750	105,001
Consolidation, Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	(112,736)	(113,518)	(103,899)
Cement [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	$ 1,226,017	$ 1,074,070	$ 1,007,094
Cement Sales Volume | kt	7,289	7,133	7,534
Operating Earnings	$ 338,349	$ 278,762	$ 259,556
Capital Expenditures	65,442	39,049	31,535
Depreciation, Depletion, and Amortization	89,138	81,643	79,560
Segment Assets	$ 2,042,499	$ 1,905,227	$ 1,860,649
Cement [Member] | Operating Segments [Member] | Wholly-Owned [Member]
Segment Reporting Information [Line Items]
Cement Sales Volume | kt	6,610	6,399	6,711
Operating Earnings	$ 306,768	$ 243,288	$ 227,068
Cement [Member] | Operating Segments [Member] | Joint Venture [Member]
Segment Reporting Information [Line Items]
Cement Sales Volume | kt	679	734	823
Operating Earnings	$ 31,581	$ 35,474	$ 32,488
Cement [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	35,363	32,915	22,915
Concrete and Aggregates [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	252,952	239,516	177,122
Operating Earnings	12,401	18,259	18,467
Capital Expenditures	15,103	35,503	5,239
Depreciation, Depletion, and Amortization	19,728	17,413	9,656
Segment Assets	225,485	234,767	89,405
Concrete and Aggregates [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	12,940	0	0
Gypsum Wallboard [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	839,530	872,471	692,152
Operating Earnings	334,536	352,499	261,476
Capital Expenditures	29,127	31,063	32,405
Depreciation, Depletion, and Amortization	23,038	21,744	22,024
Segment Assets	432,122	421,425	397,486
Paperboard [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	184,188	201,280	194,054
Operating Earnings	31,616	25,220	12,603
Capital Expenditures	10,085	2,898	2,579
Depreciation, Depletion, and Amortization	14,811	14,942	14,721
Segment Assets	170,832	163,797	180,025
Paperboard [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	82,351	92,835	82,086
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	548	1,630	2,363
Depreciation, Depletion, and Amortization	3,117	2,812	2,850
Segment Assets	$ 76,081	$ 55,786	$ 52,087