Income Taxes - Reconciliation (Details)	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Reconciliation of the U.S. federal statutory rate to the effective rate for continuing operations
U.S. statutory rate (as a percent)	35.00%	35.00%	35.00%
Permanent items (as a percent)	(4.20%)	(6.30%)	0.50%
State taxes (as a percent)	1.90%	2.60%	2.70%
Net foreign rate differential (as a percent)	(3.80%)	(3.00%)	(2.50%)
Unrecognized tax benefits	(2.20%)
Changes in valuation allowance (as a percent)	(108.80%)	(0.90%)	3.60%
Provision for income taxes (as a percent)	(82.10%)	27.40%	39.30%