Income Taxes - Reconciliation of U.S. Federal Statutory Tax Rate to Effective Tax Rate (Details)	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]
U.S. federal statutory tax rate	35.00%	35.00%	35.00%
Difference in tax rate due to:
Noncontrolling interests not subject to tax	(7.90%)	(9.00%)	(8.70%)
State income taxes, net of federal benefit	3.30%	3.40%	3.40%
Valuation allowance adjustments	0.80%	0.00%	(0.50%)
Effects of foreign operations	0.20%	1.00%	(1.80%)
Other, net	(1.40%)	0.20%	0.20%
Effective tax rate	30.00%	30.60%	27.60%