Comprehensive Income (Loss) and Accumulated Other Comprehensive (Loss) Income (Details) (USD $) In Thousands	12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2009
Comprehensive Loss Income (Details) [Abstract]
Net income (loss)	$ 232,277	$ 48,202	$ (118,631)
Unrealized gain (loss) on derivatives designated and qualified as cash flow hedges, net of income tax expense (benefit) of $0.4 million, $(0.6) million and $(1.9) million, respectively	642	(936)	(3,006)
Reclassification of unrealized (gain) loss on expired derivatives designated and qualified as cash flow hedges, net of income tax expense (benefit) of $0.4 million, $0.9 million and $(3.3) million, respectively	(679)	(1,482)	5,290
Unrecognized net pension and other postretirement benefit gains (losses), net of incometax expense (benefit) of $15.1 million, $(14.1) million and $0.6 million, respectively	28,087	(17,397)	(14,283)
Reclassification of net pension and other postretirement benefit losses, net of income tax benefit of $4.4 million, $0.9 million and $0.5 million, respectively	7,131	2,975	1,496
Foreign currency translation adjustments, net of income tax expense (benefit) of $75.0 million, $(41.5) million and $(73.5) million, respectively	122,358	(68,837)	(122,044)
Total comprehensive (loss) income, net of tax	389,816	(37,475)	(251,178)
Comprehensive income (loss) attributable to noncontrolling interests	4,779	606	(1,046)
Comprehensive income (loss) attributable to Kennametal Shareowners	$ 385,037	$ (38,081)	$ (250,132)