Reconciliation of The Federal Corporate Income Tax Rate and The Effective Tax Rate (Detail)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Investments, Owned, Federal Income Tax Note [Line Items]
Statutory income tax rate	35.00%	35.00%	35.00%
Effect of foreign operations	1.50%	0.80%	(0.50%)
State taxes, net of federal benefit	2.70%	2.90%	3.10%
Domestic Production Activities Deduction permanent difference	(2.70%)	(2.10%)	(1.50%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense	0.20%	0.80%	2.40%
Research and Experimentation and other federal tax credits	(0.80%)	(0.30%)	(0.10%)
Resolution of prior tax contingencies	0.20%	0.20%	(0.90%)
Other	(0.50%)	(0.70%)	0.30%
Effective income tax rate	35.60%	36.60%	37.80%