Leases - Components of Lease Expense (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 27, 2019
Sep. 27, 2019
Leases [Abstract]    
Operating lease expense $ 3,827 $ 10,890
Variable lease expense 196 594
Short-term lease expense 12,436 35,055
Total lease expense $ 16,459 $ 46,539