Accumulated Other Comprehensive Loss - Components of and Changes in Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	$ 1,325,597	$ 1,317,963	$ 1,324,648	$ 1,288,599
Ending Balance	1,357,657	1,260,101	1,357,657	1,260,101
Pension and other postretirement benefits attributable to Kennametal
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			(223,016)	(221,308)
Other comprehensive income (loss) before reclassifications			511	616
Amounts reclassified from AOCL			4,524	3,724
Net other comprehensive income (loss)			5,035	4,340
Ending Balance	(217,981)	(216,968)	(217,981)	(216,968)
Currency translation adjustment attributable to Kennametal
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			(165,859)	(216,263)
Other comprehensive income (loss) before reclassifications			426	(20,905)
Amounts reclassified from AOCL			0	0
Net other comprehensive income (loss)			426	(20,905)
Ending Balance	(165,433)	(237,168)	(165,433)	(237,168)
Derivatives attributable to noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			2,182	2,983
Other comprehensive income (loss) before reclassifications			(194)	1,085
Amounts reclassified from AOCL			(188)	(392)
Net other comprehensive income (loss)			(382)	693
Ending Balance	1,800	3,676	1,800	3,676
Total attributable to Kennametal
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(386,497)	(400,970)	(386,693)	(434,588)
Other comprehensive income (loss) before reclassifications			743	(19,204)
Amounts reclassified from AOCL			4,336	3,332
Net other comprehensive income (loss)			5,079	(15,872)
Ending Balance	(381,614)	(450,460)	(381,614)	(450,460)
Pension and other postretirement benefits attributable to noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			0	0
Other comprehensive income (loss) before reclassifications			0	0
Net other comprehensive income (loss)			0	0
Ending Balance	0	0	0	0
Currency translation adjustment attributable to noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			(7,844)	(8,680)
Other comprehensive income (loss) before reclassifications			(695)	(1,055)
Net other comprehensive income (loss)			(695)	(1,055)
Ending Balance	(8,539)	(9,735)	(8,539)	(9,735)
Derivatives attributable to noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			0	0
Other comprehensive income (loss) before reclassifications			0	0
Net other comprehensive income (loss)			0	0
Ending Balance	0	0	0	0
Total attributable to noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			(7,844)	(8,680)
Other comprehensive income (loss) before reclassifications			(695)	(1,055)
Net other comprehensive income (loss)			(695)	(1,055)
Ending Balance	(8,539)	(9,735)	(8,539)	(9,735)
Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	41,377	40,790	40,669	38,724
Ending Balance	42,620	40,121	42,620	40,121
Reclassification out of Accumulated Other Comprehensive Loss | Pension and other postretirement benefits attributable to Kennametal
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	(2,880)	(2,076)	(5,767)	(4,984)
Reclassification out of Accumulated Other Comprehensive Loss | Derivatives attributable to noncontrolling interests
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	$ (29)	$ (224)	$ (249)	$ (519)