Stockholders’ Equity - Narrative (Details)	6 Months Ended
	Mar. 31, 2017 item shares
RSUs
Stockholders' Equity
Number of units awarded (in shares)	1,905,460
Number of shares of common stock that each award holder has the contingent right to receive	1
Vested awards to date	445,242
Expected awards vested (in shares)	493,560
Time-based RSUs
Stockholders' Equity
Number of units awarded (in shares)	912,162
Number of equal installments for vesting of stock awards | item	4
Performance-based RSUs
Stockholders' Equity
Number of units awarded (in shares)	993,298
Vesting period	3 years
Number of vesting criteria which have to be satisfied out of total vesting criteria | item	1
Number of vesting criteria | item	3