Stock Plans (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Apr. 05, 2020	Mar. 31, 2019	Dec. 29, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total income tax benefit recognized for stock-based compensation	$ 2,200	$ 4,200
Stock-based compensation costs capitalized as part of inventory	300	400
Proceeds from issuance of common stock under stock plans	1,106	8,610
Total pre-tax stock-based compensation expense	$ 3,050	$ 6,097
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value of options	$ 18.98	$ 22.66
Total intrinsic value of options exercised	$ 900	$ 8,800
Proceeds from issuance of common stock under stock plans	1,100	8,600
Total pre-tax stock-based compensation expense	1,000	1,400
Total unrecognized compensation cost, net of estimated forfeitures, related to nonvested stock, granted	$ 8,100
Weighted-average period for recognition of unrecognized compensation cost, years	2 years 3 months 18 days
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense	$ 2,400
Total unrecognized compensation cost, net of estimated forfeitures, related to nonvested stock, granted	$ 23,100
Weighted-average period for recognition of unrecognized compensation cost, years	2 years 1 month 6 days
Awards/units outstanding	320,000		345,000
Number of Shares, Granted	156,000
Weighted-average grant-date fair value of stock granted (per share)	$ 84.18
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	16,000
Fair value of restricted stock awards vested	$ 11,600	9,300
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense	$ (1,000)	$ 1,200
Awards/units outstanding	31,207
Number of Shares, Granted	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	1,948
Deferred Compensation Share-based Arrangements, Liability, Current and Noncurrent	$ 2,300
Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted	376
Weighted-average grant-date fair value of stock granted (per share)	$ 76.33
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under plan	5,000,000.0
Number of Shares, Granted	13,612	18,562
Weighted-average grant-date fair value of stock granted (per share)	$ 92.25	$ 74.62
Shares available for grant under employee stock purchase plan	800,000
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense	$ 600	$ 800
Awards/units outstanding	131,842
Number of Shares, Granted	89,986
Weighted-average grant-date fair value of stock granted (per share)	$ 76.76
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	19,860
2019 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under plan			6,250,000