Stock-Based Compensation (Tables)

6 Months Ended

Mar. 31, 2020

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of stock-based compensation expense

	Three Months Ended March 31,				Six Months Ended March 31,
	2020		2019		2020		2019
Restricted stock units	$	3,921	$	4,923	$	8,014	$	8,883
Employee stock purchase plan		293		198		610		414
Total stock-based compensation expense	$	4,214	$	5,121	$	8,624	$	9,297

Restricted Stock Unit Activity

		Time-Based	Stock	Performance-
	Total Units	Units	Grants	Based Units
Six months ended March 31, 2020	408,827	163,390	23,867	221,570
Six months ended March 31, 2019	789,409	327,500	38,520	423,389

		Weighted
		Average
		Grant-Date
	Shares	Fair Value
Outstanding at September 30, 2019	1,782,726	$	24.63
Granted	408,827		46.64
Vested	(890,778)		26.01
Forfeited	(97,363)		34.86
Outstanding at March 31, 2020	1,203,412		36.04