Per Share Amounts and Common Shares Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2024	Jul. 01, 2023	Jun. 29, 2024	Jul. 01, 2023
Equity [Abstract]
Net income	$ 29,720	$ 32,043	$ 27,445	$ 38,039
Weighted-average shares outstanding, basic	41,110,000	42,270,000	41,313,000	42,507,000
Weighted-average shares, partially-paid share subscriptions	304,000	324,000	609,000	649,000
Basic weighted average shares	41,414,000	42,594,000	41,922,000	43,156,000
Incremental shares from assumed exercise of stock subscription purchase rights	71,000	5,000	72,000	5,000
Incremental shares from assumed exercise of stock options and awards	1,903,000	2,163,000	1,852,000	2,102,000
Diluted weighted-average shares	43,388,000	44,762,000	43,846,000	45,263,000
Net income per share basic	$ 0.72	$ 0.75	$ 0.65	$ 0.88
Net income per share diluted	$ 0.68	$ 0.72	$ 0.63	$ 0.84
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding at January 1, 2024			41,347,394
Shares purchased			(1,805,728)
Shares sold			858,391
Stock subscription offering -- cash purchases			12,323
Options and awards exercised			889,372
Shares outstanding at June 29, 2024	41,301,752		41,301,752
Employee options exercisable	1,273,443		1,273,443
Common stock, shares subscribed but unissued	1,217,550		1,217,550
Purchase rights, outstanding	435,961		435,961
Common shares, net of treasury shares [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding at January 1, 2024			32,848,308
Shares purchased			(1,229,556)
Shares sold			467,879
Stock subscription offering -- cash purchases			12,323
Options and awards exercised			889,372
Shares outstanding at June 29, 2024	32,988,326		32,988,326
Redeemable shares [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding at January 1, 2024			8,499,086
Shares purchased			(576,172)
Shares sold			390,512
Stock subscription offering -- cash purchases			0
Options and awards exercised			0
Shares outstanding at June 29, 2024	8,313,426		8,313,426
Stock option plans [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee options exercisable	1,273,443		1,273,443