Basis of Presentation and Preparation - Contingent Consideration, and Concentration of Credit Risk (Details)	12 Months Ended
	Sep. 27, 2020 Institution
Concentration of Credit Risk
Financial institutions, in any such number of which investment exposure is limited	1
Accounts receivable due from various agencies of the U.S. federal government (as a percent)	28.00%
Minimum
Contingent Consideration
Period for contingent earn-out payments	2 years
Maximum
Contingent Consideration
Period for contingent earn-out payments	3 years
U.S. government
Concentration of Credit Risk
Revenue from customers (as a percent)	48.00%
U.S. commercial
Concentration of Credit Risk
Revenue from customers (as a percent)	22.00%
International
Concentration of Credit Risk
Revenue from customers (as a percent)	30.00%