Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balance at Dec. 26, 2020	$ 42,190	$ 448,194	$ 26,230	$ (4,326)	$ 0	$ 512,288
Net income	0	0	27,607	0	0	27,607
Changes in cumulative translation adjustment	0	0	0	(10,246)	0	(10,246)
Adjustments related to postretirement benefits, net of tax	0	0	0	(180)	0	(180)
Changes in unrealized gains and losses on investments, net of tax	0	0	0	(6)	0	(6)
Exercise of stock options	192	1,730	0	0	0	1,922
Shares issued for restricted stock units vested	526	(526)	0	0	0	0
Repurchase and retirement of stock	(190)	(8,363)	0	0	0	(8,553)
Share-based compensation expense	0	3,523	0	0	0	3,523
Sale of common stock, net of issuance costs	5,693	217,426	0	0	0	223,119
Balance at Mar. 27, 2021	48,411	661,984	53,837	(14,758)	0	749,474
Balance at Dec. 25, 2021	48,756	674,777	193,555	(27,262)	(7,324)	882,502	[1]
Net income	0	0	21,569	0	0	21,569
Changes in cumulative translation adjustment	0	0	0	(8,903)	0	(8,903)
Adjustments related to postretirement benefits, net of tax	0	0	0	(61)	0	(61)
Changes in unrealized gains and losses on investments, net of tax	0	0	0	(348)	0	(348)
Shares issued for restricted stock units vested	426	(426)	0	0	0	0
Repurchase and retirement of stock	(157)	(4,739)	0	0	0	(4,896)
Share-based compensation expense	0	3,422	0	0	0	3,422
Common stock repurchases	0	0	0	0	(6,388)	(6,388)
Balance at Mar. 26, 2022	$ 49,025	$ 673,034	$ 215,124	$ (36,574)	$ (13,712)	$ 886,897

[1] Derived from December 25, 2021 audited financial statements