Financial Information Related to Operations by Segment (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2022 USD ($) kt	Sep. 30, 2021 USD ($) kt	Sep. 30, 2022 USD ($) kt	Sep. 30, 2021 USD ($) kt	Mar. 31, 2022 USD ($)
Segment Reporting Information [Line Items]
Revenue	$ 605,068	$ 509,694	$ 1,166,455	$ 985,464
Less: Joint Venture Revenue	(25,130)	(26,926)	(51,445)	(49,617)
Operating Earnings	201,395	163,601	357,359	298,082
Corporate General and Administrative Expense	(13,627)	(10,667)	(25,447)	(20,135)
Loss on Early Retirement of Senior Notes	0	(8,407)	0	(8,407)
Other Non-Operating Income	(664)	(944)	(1,299)	2,734
Earnings Before Interest and Income Taxes	187,104	143,583	330,613	272,274
Interest Expense, net	(8,580)	(12,268)	(15,910)	(19,240)
Earnings from Continuing Operations Before Income Taxes	178,524	131,315	314,703	253,034
Capital Expenditures	28,335	14,842	43,249	26,777
Depreciation, Depletion and Amortization			68,874	64,284
Identifiable Assets	2,809,149		2,809,149		$ 2,579,652
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	667,384	561,857	1,283,918	1,086,400
Depreciation, Depletion and Amortization	34,645	32,340	68,874	64,284
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	(37,186)	(25,237)	(66,018)	(51,319)
Revenue	37,186	25,237	66,018	51,319
Cement [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	$ 319,460	$ 288,324	$ 603,976	$ 558,579
Cement Sales Volume | kt	2,145	2,198	4,138	4,234
Operating Earnings	$ 98,779	$ 88,750	$ 161,127	$ 151,297
Capital Expenditures	4,893	6,976	13,879	14,943
Depreciation, Depletion and Amortization	20,258	$ 20,019	40,311	$ 39,550
Identifiable Assets	$ 1,903,575		$ 1,903,575		1,860,649
Cement [Member] | Operating Segments [Member] | Wholly-Owned [Member]
Segment Reporting Information [Line Items]
Cement Sales Volume | kt	1,981	1,983	3,786	3,835
Operating Earnings	$ 91,623	$ 80,490	$ 148,873	$ 135,067
Cement [Member] | Operating Segments [Member] | Joint Venture [Member]
Segment Reporting Information [Line Items]
Cement Sales Volume | kt	164	215	352	399
Operating Earnings	$ 7,156	$ 8,260	$ 12,254	$ 16,230
Cement [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	12,361	5,223	18,652	13,056
Concrete and Aggregates [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	69,613	52,750	131,231	97,504
Operating Earnings	7,276	7,539	13,008	12,883
Capital Expenditures	13,688	527	14,340	1,073
Depreciation, Depletion and Amortization	4,351	2,470	8,552	5,048
Identifiable Assets	224,578		224,578		89,405
Gypsum Wallboard [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	224,638	172,985	440,965	339,252
Operating Earnings	89,761	66,331	173,829	129,584
Capital Expenditures	8,391	6,345	12,470	8,039
Depreciation, Depletion and Amortization	5,589	5,484	11,152	10,880
Identifiable Assets	396,655		396,655		397,486
Paperboard [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	53,673	47,798	107,746	91,065
Operating Earnings	5,579	981	9,395	4,318
Capital Expenditures	1,018	375	1,855	1,492
Depreciation, Depletion and Amortization	3,742	3,663	7,459	7,331
Identifiable Assets	174,261		174,261		180,025
Paperboard [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	24,825	20,014	47,366	38,263
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Capital Expenditures	345	619	705	1,230
Depreciation, Depletion and Amortization	705	$ 704	1,400	$ 1,475
Other, net [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	$ 110,080		$ 110,080		$ 52,087