Operations and summary of significant accounting policies (Schedule of finite-lived intangible assets useful lives) (Details)	12 Months Ended
	Sep. 30, 2011 years
Customer Relationships [Member]
Finite-Lived Intangible Assets, Useful Life, Minimum	9
Finite-Lived Intangible Assets, Useful Life, Maximum	30
Intellectual Property [Member]
Finite-Lived Intangible Assets, Useful Life, Minimum	10
Finite-Lived Intangible Assets, Useful Life, Maximum	17
Process Technology [Member]
Finite-Lived Intangible Assets, Useful Life, Minimum	8
Finite-Lived Intangible Assets, Useful Life, Maximum	30
Other Intangibles [Member]
Finite-Lived Intangible Assets, Useful Life, Minimum	1
Finite-Lived Intangible Assets, Useful Life, Maximum	15