Customer Contracts - Allowance for Doubtful Accounts (Details) $ in Millions	6 Months Ended
	Jun. 28, 2020 USD ($)
Allowance for doubtful accounts (in millions):
Balance at beginning of period	$ 10.2
Accruals for credit loss charged to expense	2.8
Other deductions	(1.0)
Balance at end of period	$ 12.0