Leases - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Apr. 04, 2020	Apr. 04, 2020	Oct. 03, 2020	Sep. 28, 2019	Sep. 29, 2018
Lessee, Lease, Description [Line Items]
Asset impairment charges	$ 2,500
Right of use assets, net - operating leases (See Note 11)			$ 85,905	$ 0
Operating cash outflows from operating leases			19,391	$ 22,900	$ 22,100
Right-Of-Use Assets | Industrial Lasers & Systems
Lessee, Lease, Description [Line Items]
Asset impairment charges		$ 1,800	1,800
Building
Lessee, Lease, Description [Line Items]
Sale and leaseback transaction, gain (loss), net			19,600
Right of use assets, net - operating leases (See Note 11)			5,100
Present value of total operating lease liabilities			5,100
Other non-cash expense (gain)			4,000
Building | Selling, General and Administrative Expenses
Lessee, Lease, Description [Line Items]
Sale and leaseback transaction, gain (loss), net			$ 2,200
Building | Minimum
Lessee, Lease, Description [Line Items]
Sale leaseback transaction, lease terms			6
Leases, early termination provisions			3 years
Building | Maximum
Lessee, Lease, Description [Line Items]
Sale leaseback transaction, lease terms			15
Leases, early termination provisions			5 years