Share-Based Compensation - Nonvested Shares (Details) - 2007 Plan - Restricted Stock Units (RSUs) - shares	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested shares, beginning balance	6,773,132	6,334,903	1,920,887
Granted	5,521,521	9,764,906	6,541,439
Forfeited	(858,710)	(1,201,823)	(710,743)
Vested	(3,714,069)	(8,124,854)	(1,416,680)
Non-vested shares, ending balance	7,721,874	6,773,132	6,334,903