Leases (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Dec. 30, 2018	Sep. 28, 2019	Sep. 28, 2019
Leases
Operating lease right-of-use assets		$ 110,999	$ 110,999
Recognize lease liabilities		137,467	137,467
Options to extend	true
Lease expenses included in income statement
Operating lease cost		4,052	11,276
Short-term lease cost		106	295
Variable lease cost		1,181	3,150
Total lease cost		5,339	14,721
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases			12,053
Right-of-use assets obtained in exchange for lease obligations
Operating leases			37,298
Assets
Operating lease right-of-use assets		110,999	110,999
Liabilities:
Current portion of lease liabilities		10,598	10,598
Non-current portion of lease liabilities		126,869	126,869
Total operating lease liabilities		$ 137,467	$ 137,467
Weighted average remaining lease term - operating leases		9 years 9 months 18 days	9 years 9 months 18 days
Weighted average discount rate - operating leases		3.70%	3.70%
Minimum
Leases
Remaining lease terms	1 year
Maximum
Leases
Remaining lease terms	12 years
Lease extension term	5 years
ASU 2016-02
Leases
Operating lease right-of-use assets	$ 82,300	$ 82,300	$ 82,300
Recognize lease liabilities	106,800	106,800	106,800
Assets
Operating lease right-of-use assets	82,300	82,300	82,300
Liabilities:
Total operating lease liabilities	$ 106,800	$ 106,800	$ 106,800