Significant Accounting Policies (Segment Reporting Revenue Percentage) (Detail)	3 Months Ended		9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Reinforcement Materials [Member]
Depreciation Amortization Impairment [Line Items]
Revenue, by segment	55.00%	63.00%	57.00%	65.00%
Performance Materials [Member]
Depreciation Amortization Impairment [Line Items]
Revenue, by segment	27.00%	30.00%	27.00%	29.00%
Advanced Technologies [Member]
Depreciation Amortization Impairment [Line Items]
Revenue, by segment	8.00%	7.00%	6.00%	6.00%
Purification Solutions [Member]
Depreciation Amortization Impairment [Line Items]
Revenue, by segment	10.00%		10.00%