Leases - Supplemental cash flow information (Details) $ in Thousands	3 Months Ended
	Mar. 30, 2019 USD ($)
Cash Flow, Lessee [Abstract]
Operating cash flows from operating leases	$ 31,557
Operating cash flows from finance leases	31
Financing cash flows from finance leases	371
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	22,243
Finance leases	0
Amortization of right of use operating lease assets	$ 28,641