Segment Information - Financial Information Related to Operations by Segment (Detail) $ in Thousands		3 Months Ended
		Jun. 30, 2025 USD ($) kt	Jun. 30, 2024 USD ($) kt	Mar. 31, 2025 USD ($)
Segment Reporting Information [Line Items]
Revenue		$ 634,690	$ 608,689
Corporate General and Administrative Expense		(20,783)	(15,649)
Other Non-Operating Income (Loss)		954	2,683
Interest Expense, net		(11,716)	(10,684)
Earnings before Income Taxes		157,858	170,934
Capital Expenditures		76,097	33,128
Depreciation, Depletion and Amortization		40,644	38,350
Segment Assets		3,397,314		$ 3,264,588
External Customers [Member]
Segment Reporting Information [Line Items]
Revenue		634,690	608,689
Intersegment [Member]
Segment Reporting Information [Line Items]
Revenue		35,837	38,044
Joint Venture [Member]
Segment Reporting Information [Line Items]
Revenue		27,283	29,310
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue		697,810	676,043
Freight and Delivery		74,339	69,709
Parts, Supplies, and Services (Includes Maintenance)		94,803	91,442
Energy		47,655	46,686
Raw Materials		118,778	120,592
Labor and Fixed Costs		76,514	70,544
Depreciation, Depletion and Amortization	[1]	39,820	37,610
Purchased Cement		17,274	20,819
Other Segment Items		39,224	24,057
Segment Profit		189,403	194,584
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue		(35,837)	(38,044)
Consolidation, Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue		(27,283)	(29,310)
Cement [Member] | External Customers [Member]
Segment Reporting Information [Line Items]
Revenue		310,326	299,572
Cement [Member] | Intersegment [Member]
Segment Reporting Information [Line Items]
Revenue		10,013	10,280
Cement [Member] | Joint Venture [Member]
Segment Reporting Information [Line Items]
Revenue		27,283	29,310
Cement [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue		$ 347,622	$ 339,162
Cement Sales Volume | kt		1,993	1,947
Operating Earnings		$ 81,084	$ 89,125
Capital Expenditures		45,995	18,794
Freight and Delivery		28,078	27,148
Parts, Supplies, and Services (Includes Maintenance)		74,706	74,906
Energy		32,780	33,897
Raw Materials		21,160	20,998
Labor and Fixed Costs		44,509	41,621
Depreciation, Depletion and Amortization	[1]	22,838	22,917
Purchased Cement		17,274	20,819
Other Segment Items		25,193	7,731
Segment Profit		81,084	$ 89,125
Segment Assets		$ 2,240,842		2,172,459
Cement [Member] | Operating Segments [Member] | Wholly-Owned [Member]
Segment Reporting Information [Line Items]
Cement Sales Volume | kt		1,835	1,767
Operating Earnings		$ 77,280	$ 81,409
Cement [Member] | Operating Segments [Member] | Joint Venture [Member]
Segment Reporting Information [Line Items]
Cement Sales Volume | kt		158	180
Operating Earnings		$ 3,804	$ 7,716
Concrete and Aggregates [Member] | External Customers [Member]
Segment Reporting Information [Line Items]
Revenue		73,716	61,038
Concrete and Aggregates [Member] | Intersegment [Member]
Segment Reporting Information [Line Items]
Revenue		3,852	3,777
Concrete and Aggregates [Member] | Joint Venture [Member]
Segment Reporting Information [Line Items]
Revenue		0	0
Concrete and Aggregates [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue		77,568	64,815
Capital Expenditures		5,603	6,589
Freight and Delivery		6,889	6,032
Parts, Supplies, and Services (Includes Maintenance)		11,633	8,095
Energy		2,200	1,927
Raw Materials		29,057	29,901
Labor and Fixed Costs		10,023	8,000
Depreciation, Depletion and Amortization	[1]	6,791	4,530
Purchased Cement		0	0
Other Segment Items		4,800	3,350
Segment Profit		6,175	2,980
Segment Assets		411,398		408,792
Gypsum Wallboard [Member] | External Customers [Member]
Segment Reporting Information [Line Items]
Revenue		221,516	217,826
Gypsum Wallboard [Member] | Intersegment [Member]
Segment Reporting Information [Line Items]
Revenue		0	0
Gypsum Wallboard [Member] | Joint Venture [Member]
Segment Reporting Information [Line Items]
Revenue		0	0
Gypsum Wallboard [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue		221,516	217,826
Capital Expenditures		21,995	3,280
Freight and Delivery		39,372	36,485
Parts, Supplies, and Services (Includes Maintenance)		5,354	3,930
Energy		8,597	7,597
Raw Materials		46,667	47,071
Labor and Fixed Costs		16,117	15,462
Depreciation, Depletion and Amortization	[1]	6,519	6,473
Purchased Cement		0	0
Other Segment Items		6,249	6,832
Segment Profit		92,641	93,976
Segment Assets		446,772		429,268
Recycled Paperboard [Member] | External Customers [Member]
Segment Reporting Information [Line Items]
Revenue		29,132	30,253
Recycled Paperboard [Member] | Intersegment [Member]
Segment Reporting Information [Line Items]
Revenue		21,972	23,987
Recycled Paperboard [Member] | Joint Venture [Member]
Segment Reporting Information [Line Items]
Revenue		0	0
Recycled Paperboard [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue		51,104	54,240
Capital Expenditures		1,315	3,561
Freight and Delivery		0	44
Parts, Supplies, and Services (Includes Maintenance)		3,110	4,511
Energy		4,078	3,265
Raw Materials		21,894	22,622
Labor and Fixed Costs		5,865	5,461
Depreciation, Depletion and Amortization	[1]	3,672	3,690
Purchased Cement		0	0
Other Segment Items		2,982	6,144
Segment Profit		9,503	8,503
Segment Assets		161,091		166,673
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Capital Expenditures		1,189	$ 904
Segment Assets		$ 137,211		$ 87,396

[1] Depreciation, Depletion, and Amortization for corporate assets was $824 and $740 for the three months ended June 30, 2025, and 2024, respectively.