Segment Data - Sales and Operating (Loss) Income by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024	Jun. 30, 2025
External sales:
Sales	$ 529,525	$ 482,051	$ 1,027,499	$ 963,999
Restructuring and other charges, net	2,528	1,335	4,117	1,946
Amortization of intangibles	2,378	2,720	4,751	5,438
Operating (income) loss:
Total operating income	52,661	31,667	90,221	67,693
Interest expense	6,089	6,180	12,275	12,493
Other income, net	(2,097)	(1,477)	(4,418)	(3,136)
Income before income taxes	48,669	26,964	82,364	58,336
Depreciation and amortization:	34,368	34,011	69,413	67,568
Segment assets	2,595,556	2,435,805	2,595,556	2,435,805	$ 2,545,412
Total capital expenditures	$ 12,711	$ 19,220	$ 35,692	$ 43,967
General Engineering
Operating (income) loss:
Revenues, percent	45.00%	46.00%	45.00%	46.00%
Transportation
Operating (income) loss:
Revenues, percent	16.00%	16.00%	16.00%	16.00%
Aerospace & Defense
Operating (income) loss:
Revenues, percent	13.00%	11.00%	13.00%	11.00%
Energy
Operating (income) loss:
Revenues, percent	12.00%	14.00%	12.00%	13.00%
Earthworks
Operating (income) loss:
Revenues, percent	14.00%	13.00%	14.00%	14.00%
Americas
Operating (income) loss:
Revenues, percent	50.00%	49.00%	50.00%	49.00%
Europe, the Middle East and Africa (EMEA)
Operating (income) loss:
Revenues, percent	30.00%	30.00%	30.00%	30.00%
Asia Pacific
Operating (income) loss:
Revenues, percent	20.00%	21.00%	20.00%	21.00%
Metal Cutting
External sales:
Sales	$ 331,059	$ 297,786	$ 641,684	$ 594,686
Cost of goods sold	211,270	195,358	412,045	382,864
Operating expense	88,039	84,324	174,212	168,895
Amortization of intangibles	396	380	792	759
Operating (income) loss:
Total operating income	29,758	16,586	51,322	40,408
Depreciation and amortization:	23,762	23,332	48,210	46,331
Segment assets	1,386,239	1,363,197	1,386,239	1,363,197
Capital expenditures:	$ 5,622	$ 12,145	$ 16,821	$ 28,425
Metal Cutting | General Engineering
Operating (income) loss:
Revenues, percent	54.00%	54.00%	53.00%	54.00%
Metal Cutting | Transportation
Operating (income) loss:
Revenues, percent	25.00%	26.00%	25.00%	26.00%
Metal Cutting | Aerospace & Defense
Operating (income) loss:
Revenues, percent	14.00%	13.00%	14.00%	13.00%
Metal Cutting | Energy
Operating (income) loss:
Revenues, percent	7.00%	7.00%	8.00%	7.00%
Metal Cutting | Earthworks
Operating (income) loss:
Revenues, percent	0.00%	0.00%	0.00%	0.00%
Metal Cutting | Americas
Operating (income) loss:
Revenues, percent	46.00%	44.00%	46.00%	45.00%
Metal Cutting | Europe, the Middle East and Africa (EMEA)
Operating (income) loss:
Revenues, percent	35.00%	36.00%	36.00%	36.00%
Metal Cutting | Asia Pacific
Operating (income) loss:
Revenues, percent	19.00%	20.00%	18.00%	19.00%
Infrastructure
External sales:
Sales	$ 198,466	$ 184,265	$ 385,815	$ 369,313
Cost of goods sold	144,355	141,663	286,950	285,095
Operating expense	27,796	24,449	54,060	51,006
Restructuring and other charges, net	933	197	804	187
Amortization of intangibles	1,981	2,340	3,960	4,679
Operating (income) loss:
Total operating income	23,402	15,612	40,042	28,347
Depreciation and amortization:	10,606	10,679	21,203	21,237
Segment assets	748,730	679,169	748,730	679,169
Capital expenditures:	$ 7,089	$ 7,075	$ 18,871	$ 15,542
Infrastructure | General Engineering
Operating (income) loss:
Revenues, percent	31.00%	33.00%	31.00%	33.00%
Infrastructure | Transportation
Operating (income) loss:
Revenues, percent	0.00%	0.00%	0.00%	0.00%
Infrastructure | Aerospace & Defense
Operating (income) loss:
Revenues, percent	10.00%	9.00%	11.00%	9.00%
Infrastructure | Energy
Operating (income) loss:
Revenues, percent	21.00%	24.00%	21.00%	23.00%
Infrastructure | Earthworks
Operating (income) loss:
Revenues, percent	38.00%	34.00%	37.00%	35.00%
Infrastructure | Americas
Operating (income) loss:
Revenues, percent	57.00%	56.00%	57.00%	56.00%
Infrastructure | Europe, the Middle East and Africa (EMEA)
Operating (income) loss:
Revenues, percent	20.00%	21.00%	21.00%	21.00%
Infrastructure | Asia Pacific
Operating (income) loss:
Revenues, percent	23.00%	23.00%	22.00%	23.00%
Metal Cutting
External sales:
Restructuring and other charges, net	$ 1,595	$ 1,138	$ 3,313	$ 1,759
Total KMT
Operating (income) loss:
Total operating income	53,160	32,198	91,364	68,755
Corporate Segment
Operating (income) loss:
Total operating income	(499)	(531)	(1,143)	(1,062)
Segment assets	$ 460,587	$ 393,439	$ 460,587	$ 393,439