Income Taxes - Reconciliation of Federal Statutory Tax Rate to Company's Effective Tax Rate (Detail)	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Federal statutory tax rate	35.00%	35.00%	35.00%
State and local income taxes, net of federal tax benefit	(3.60%)	(0.50%)	(1.20%)
Effect of foreign and Puerto Rico earnings and foreign tax credits	(24.50%)	(11.20%)	(9.70%)
Effect of Research Credits and Domestic Production Activities,	(1.60%)	(1.10%)	(3.80%)
Other, net	0.60%	(0.10%)	(0.10%)
Total	5.90%	22.10%	20.20%