Leases - Lease Balances (Details) - USD ($) $ in Thousands	Sep. 28, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Right-of-use assets	$ 48,684	$ 46,162	$ 0
Short-term lease liability		8,892
Long-term lease liability	44,375	$ 42,639	$ 0
Total liability	53,150
Right-of-use assets
Lessee, Lease, Description [Line Items]
Right-of-use assets	48,684
Accrued Liabilities
Lessee, Lease, Description [Line Items]
Short-term lease liability	8,775
Long-term lease
Lessee, Lease, Description [Line Items]
Long-term lease liability	$ 44,375