401(k) and Profit Sharing Plan (Details) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, expense recognized	$ 6,200,000	$ 6,500,000	$ 7,100,000
Defined contributionplan, plan name	401(k) Plans
Profit sharing plan, expense recognized	$ 0	$ 0	$ 0
U.S. 401(k) Plan
Defined Benefit Plan Disclosure [Line Items]
Defined contributionplan, plan name	U.S. 401(k) Plan
Puerto Rico 401(k) Plan
Defined Benefit Plan Disclosure [Line Items]
Defined contributionplan, plan name	Puerto Rico 401(k) Plan
Defined Contribution Plan, minimum employment period for contribution to plan	1 year