Stock-Based Compensation - Weighted Average Fair Value (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended			12 Months Ended
	Jun. 30, 2020	Jul. 02, 2019	Jun. 30, 2020	Jul. 02, 2019	Jul. 02, 2019	Dec. 31, 2019
Stock Options
Stock option activity, Shares
Outstanding at beginning of year (in shares)			1,829
Granted (in shares)			654
Exercised (in shares)	0		(4)
Forfeited or cancelled (in shares)			(43)
Outstanding at end of year (in shares)	2,436		2,436			1,829
Exercisable at end of year (in shares)	1,214		1,214
Weighted Average Exercise Price
Outstanding at beginning of year (in dollars per share)			$ 47.32
Granted (in dollars per share)			40.16
Exercised (in dollars per share)			29.79
Forfeited or cancelled (in dollars per share)			48.21
Outstanding at end of year (in dollars per share)	$ 45.41		45.41			$ 47.32
Exercisable at end of year (in dollars per share)	$ 46.77		$ 46.77
Weighted Average Remaining Contractual Term (In years)
Weighted Average Remaining Contractual Term (In years)			5 years 4 months 24 days			4 years 3 months 18 days
Exercisable at end of year (In years)			2 years 9 months 18 days
Aggregate Intrinsic Value
Outstanding at beginning of year			$ 844
Outstanding at end of year	$ 9,783		9,783			$ 844
Exercisable at end of year	$ 5,696		5,696
Shares issued during the period	0	0
Total intrinsic value of options exercised		$ 200	35,600		$ 3,600
Unrecognized Stock-based Compensation Expense
Total unrecognized stock-based compensation expenses related to unvested stock options, restricted shares and restricted share units	$ 9,400		$ 9,400
Expected weighted average period for recognition of compensation expense related to unvested stock option			5 years 2 months 12 days
Restricted Shares and Restricted Share Units
Restricted Shares and Restricted Share Units, Shares
Outstanding at beginning of year (in shares)			1,764
Granted (in shares)			586
Vested (in shares)			(247)
Forfeited (in shares)			(106)
Outstanding at end of year (in shares)	1,997		1,997			1,764
Fair value of shares vested	$ 1,800	$ 1,300	$ 12,400	$ 12,400
Weighted Average Fair Value
Outstanding at beginning of year (in dollars per share)			$ 47.76
Granted (in dollars per share)	$ 23.56	$ 45.15	39.80
Vested (in dollars per share)			50.20
Forfeited (in dollars per share)			52.41
Outstanding at end of year (in dollars per share)	$ 44.87		$ 44.87			$ 47.76
Unrecognized Stock-based Compensation Expense
Total unrecognized stock-based compensation expenses related to unvested stock options, restricted shares and restricted share units	$ 44,600		$ 44,600
Expected weighted average period for recognition of compensation expense related to unvested stock option			3 years 2 months 12 days