Stock-Based Compensation (Tables)

9 Months Ended

Jun. 30, 2021

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

Summary of stock-based compensation expense

	Three Months Ended June 30,				Nine Months Ended June 30,
	2021		2020		2021		2020
Restricted stock units	$	5,475	$	3,348	$	18,667	$	11,361
Employee stock purchase plan		611		377		1,610		987
Total stock-based compensation expense	$	6,086	$	3,725	$	20,277	$	12,348

Restricted Stock Unit Activity

		Time-Based	Stock	Performance-
	Total Units	Units	Grants	Based Units
Nine months ended June 30, 2021	346,172	162,842	14,683	168,647
Nine months ended June 30, 2020	411,967	163,390	27,007	221,570

		Weighted
		Average
		Grant-Date
	Shares	Fair Value
Outstanding at September 30, 2020	1,183,009	$	36.10
Granted	346,172		71.81
Vested	(406,764)		36.01
Forfeited	(32,600)		44.27
Outstanding at June 30, 2021	1,089,817		47.23