Share-Based Compensation (Tables)

12 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Share-based Payment Award, Stock options, Valuation Assumptions

Fair value is estimated at the grant date based on a Black-Scholes-Merton option-pricing model using the following weighted-average assumptions:

	Year Ended September 30,
	2021		2020 (1)		2019
Expected stock price volatility	38	%	—	%	27	%
Expected dividend yield	—	%	—	%	—	%
Risk free interest rate	1.68	%	—	%	1.86	%
Average expected life (in years)	4.50		0.00		6.05

(1) There were no stock options granted under the plan during the year ended September 30, 2020.

Share-based Compensation, Stock Options, Activity

The following is a summary of stock option activity for the year ended September 30, 2021:

	Shares Available for Grant	Number of Options Outstanding	Weighted Average  Exercise Price		Weighted Average Grant Date Fair Value		Weighted Average Remaining Term (in years)	Aggregate Intrinsic Value ($ millions)
Balances as of September 30, 2020	724,483	1,408,036	$	38.79	$	11.38	4.16	$	17.4
Additional shares authorized by shareholders	1,000,000	—
Granted	(277,700)	277,700	$	58.64	$	19.83
Exercised	—	(333,121)	$	28.71	$	12.74
Forfeited	122,014	(122,014)	$	47.13	$	12.22
Expired	1,001	(1,001)	$	41.83	$	9.04
Balances as of September 30, 2021	1,569,798	1,229,600	$	45.17	$	12.82	4.21	$	25.5
Exercisable at September 30, 2021		237,040	$	31.83	$	11.94	0.56	$	8.1

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range

The options outstanding as of September 30, 2021 broken down by exercise price are as follows:

Exercise Price					Number of Options Outstanding	Weighted Average Exercise Price		Weighted Average Remaining Term (in Years)
$	—	-	$	5.00	—	n/a		n/a
$	5.00	-	$	10.00	—	n/a		n/a
$	10.00	-	$	15.00	—	n/a		n/a
$	15.00	-	$	20.00	—	n/a		n/a
$	20.00	-	$	25.00	—	n/a		n/a
$	25.00	-	$	30.00	149,706	$	25.91	0.37
$	30.00	-	$	35.00	—	n/a		n/a
$	35.00	-	$	40.00	80,729	$	39.79	1.37
$	40.00	-	$	45.00	739,315	$	44.94	4.92
$	45.00	-	$	50.00	—	n/a		n/a
$	50.00	-	$	55.00	—	n/a		n/a
$	55.00	-	$	60.00	259,850	$	58.61	5.27
					1,229,600	$	30.75	5.64

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

The following is a summary of restricted stock activity through September 30, 2021:

	Shares Available for Grant	Number of Shares Outstanding	Weighted Average Grant Date Fair Value		Weighted Average Remaining Term (in years)	Aggregate Intrinsic Value ($ millions)
Balances as of September 30, 2020	861,454	484,346	$	42.97	1.37	$	24.8
Granted	(307,204)	307,204	$	57.33
Vested	—	(210,461)	$	43.11
Forfeited	4,048	(4,048)	$	41.81
Balances as of September 30, 2021	558,298	577,041	$	50.57	1.26	$	38.0