XML 167 R140.htm IDEA: XBRL DOCUMENT v3.8.0.1
Equity Incentive Plans - Restricted Stock Unit Activity - Additional Information (Details) - Restricted Stock Units (RSUs) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Granted (in dollars per share) $ 14.43 $ 10.84 $ 11.89
Fair value of restricted stock awards vested $ 15.0 $ 14.3 $ 8.4
Withholding taxes remitted 4.7 4.4 2.4
Withholding taxes paid 0.1 4.3 2.3
Proceeds from employees to satisfy tax obligation $ 4.6 $ 0.1 $ 0.1