Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended														12 Months Ended
	Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013
Quarterly Financial Data [Abstract]
Sales	$ 638,970		$ 675,631		$ 694,941		$ 772,204		$ 755,242		$ 689,936		$ 619,808		$ 2,647,195	$ 2,837,190	$ 2,589,373
Gross profit	199,470		199,458		218,099		252,840		238,955		206,971		198,237		805,993	897,003	845,004
Net income (loss) attributable to Kennametal	$ (46,229)		$ (388,302)		$ 39,489		$ 45,455		$ 50,865		$ 24,209		$ 37,837		$ (373,896)	$ 158,366	$ 203,265
Basic earning (loss) per share attributable to Kennametal	$ (0.58)	[1]	$ (4.89)	[1]	$ 0.50	[1]	$ 0.58	[1]	$ 0.65	[1]	$ 0.31	[1]	$ 0.48	[1]	$ (4.71)	$ 2.01	$ 2.56
Diluted earning (loss) per share attributable to Kennametal	$ (0.58)	[1]	$ (4.89)	[1]	$ 0.49	[1]	$ 0.57	[1]	$ 0.64	[1]	$ 0.30	[1]	$ 0.48	[1]	$ (4.71)	$ 1.99	$ 2.52

[1] Earnings per share amounts attributable to Kennametal for each quarter are computed using the weighted average number of shares outstanding during the quarter. Earnings per share amounts attributable to Kennametal for the full year are computed using the weighted average number of shares outstanding during the year. Thus, the sum of the four quarters’ earnings per share attributable to Kennametal does not always equal the full-year earnings per share attributable to Kennametal.