Stock-Based Compensation - Schedule Of Summary Of Restricted Stock Unit Activity (Details)	12 Months Ended
	Sep. 30, 2020 $ / shares shares
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Beginning balance	$ 165.64
Weighted Average Grant Date Fair Value, Ending balance	$ 137.84
Performance Shares [Member] | Two Thousand Fourteen Equity Incentive Plan [Member]
Outstanding Restricted Stock Units
Outstanding Stock Units, Beginning balance | shares	55,184
Outstanding Stock Units, Units granted | shares	152,199
Outstanding Stock Units, Units vested | shares	(42,053)
Outstanding Stock Units, Units cancelled | shares	(19,461)
Outstanding Stock Units, Ending balance | shares	145,869
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Beginning balance	$ 165.83
Weighted Average Grant Date Fair Value, Units granted	147.30
Weighted Average Grant Date Fair Value, Units vested	142.01
Weighted Average Grant Date Fair Value, Units cancelled	157.81
Weighted Average Grant Date Fair Value, Ending balance	$ 146.42
Restricted Stock Units (RSUs) [Member] | Two Thousand Fourteen Equity Incentive Plan [Member]
Outstanding Restricted Stock Units
Outstanding Stock Units, Beginning balance | shares	1,041,889
Outstanding Stock Units, Units granted | shares	1,237,609
Outstanding Stock Units, Units vested | shares	(933,413)
Outstanding Stock Units, Units cancelled | shares	(141,795)
Outstanding Stock Units, Ending balance | shares	1,204,290
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Beginning balance	$ 158.10
Weighted Average Grant Date Fair Value, Units granted	142.58
Weighted Average Grant Date Fair Value, Units vested	134.49
Weighted Average Grant Date Fair Value, Units cancelled	150.58
Weighted Average Grant Date Fair Value, Ending balance	$ 146.39