Quarterly Financial Data (Quarterly Financial Data By Results Of Operations) (Details) (USD $) In Millions, except Per Share data	3 Months Ended								12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2009	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2009
Quarterly Financial Data
Net sales	$ 483.6	$ 464.2	$ 375.6	$ 351.7	$ 364.2	$ 336.9	$ 263.8	$ 233.7	$ 1,675.1	[1]	$ 1,198.6	[1]	$ 1,362.3	[1]
Gross profit	77.0	73.1	49.1	49.8	43.7	46.3	35.6	19.2	249.0		144.8		207.2
Operating (loss) income	35.0	35.2	12.1	14.1	10.2	12.8	2.0	(13.3)	96.4		11.7		64.0
Net (loss) income	25.9	28.8	9.4	7.6	5.9	2.1	3.5	(9.3)	71.7		2.1		47.9
Net income attributable to Carpenter	$ 25.5	$ 28.6	$ 9.3	$ 7.6	$ 25.5	$ 28.6	$ 9.3	$ 7.6	$ 71.0		$ 2.1		$ 47.9
Basic earnings	$ 0.57	$ 0.64	$ 0.21	$ 0.17	$ 0.13	$ 0.05	$ 0.08	$ (0.21)	$ 1.59		$ 0.04		$ 1.08
Diluted earnings	$ 0.57	$ 0.64	$ 0.21	$ 0.17	$ 0.13	$ 0.05	$ 0.08	$ (0.21)	$ 1.59		$ 0.04		$ 1.08
Weighted average common shares outstanding, basic	44.2	44.1	44.1	44.1	44.0	44.0	44.0	43.9	44.1		43.9		43.9
Weighted average common shares outstanding, diluted	45.0	44.7	44.7	44.5	44.5	44.4	44.2	43.9	44.7		44.4		44.2

[1] Net sales were attributed to countries based on the location of the customer.