Leases - Components of Lease Expense (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 28, 2019
Jun. 28, 2019
Leases [Abstract]    
Operating lease expense $ 3,647 $ 7,063
Variable lease expense 225 398
Short-term lease expense 11,422 22,619
Total lease expense $ 15,294 $ 30,080