Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands		Cumulative Effect, Period of Adoption, Adjustment [Member] Common Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Additional Paid-in Capital [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] AOCI Attributable to Parent [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Noncontrolling Interest [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Noncontrolling Interest [Member]	Total
Balance (Accounting Standards Update 2016-02 [Member]) at Dec. 29, 2018	[1]	$ 0	$ 0	$ 10,352	$ 0	$ 0	$ 10,352
Balance at Dec. 29, 2018								$ 40,763	$ 419,690	$ 111,670	$ (25,880)	$ (299)	$ 545,944
Net income (loss)								0	0	(52,372)	0	0	(52,372)
Changes in cumulative translation adjustment								0	0	0			(14,854)
Changes in cumulative translation adjustment, attributable to parent											(14,850)		(14,854)
Changes in cumulative translation adjustment, attributable to non-controlling interest												(4)
Exercise of stock options								37	293	0	0	0	330
Shares issued for restricted stock units vested								597	(597)	0	0	0	0
Repurchase and retirement of stock								(196)	(2,562)	0	0	0	(2,758)
Share-based compensation expense								0	10,861	0	0	0	10,861
Cash dividends								0	0	(7,383)	0	0	(7,383)
Shares issued under ESPP								64	743	0	0	0	807
Adjustments related to postretirement benefits, net of tax								0	0	0	470	0	470
Noncontrolling interest								0	0	53	0	(53)	0
Balance at Sep. 28, 2019								41,265	428,428	62,320	(40,260)	(356)	491,397
Balance at Jun. 29, 2019								41,100	425,609	75,115	(27,019)	(356)	514,449
Net income (loss)								0	0	(10,326)	0	0	(10,326)
Changes in cumulative translation adjustment								0	0	0			(13,276)
Changes in cumulative translation adjustment, attributable to parent											(13,276)		(13,276)
Changes in cumulative translation adjustment, attributable to non-controlling interest												0
Exercise of stock options								22	186	0	0	0	208
Shares issued for restricted stock units vested								203	(203)	0	0	0	0
Repurchase and retirement of stock								(60)	(670)	0	0	0	(730)
Share-based compensation expense								0	3,506	0	0	0	3,506
Cash dividends								0	0	(2,469)	0	0	(2,469)
Adjustments related to postretirement benefits, net of tax								0	0	0	35	0	35
Balance at Sep. 28, 2019								41,265	428,428	62,320	(40,260)	(356)	491,397
Balance at Dec. 28, 2019								41,395	433,190	42,517	(34,030)	0	483,072
Net income (loss)								0	0	(28,662)	0	0	(28,662)
Changes in cumulative translation adjustment								0	0	0			12,660
Changes in cumulative translation adjustment, attributable to parent											12,660		12,660
Changes in cumulative translation adjustment, attributable to non-controlling interest												0
Exercise of stock options								28	347	0	0	0	375
Shares issued for restricted stock units vested								614	(614)	0	0	0	0
Repurchase and retirement of stock								(189)	(2,076)	0	0	0	(2,265)
Share-based compensation expense								0	10,313	0	0	0	10,313
Cash dividends								0	0	(2,486)	0	0	(2,486)
Shares issued under ESPP								114	1,488	0	0	0	1,602
Adjustments related to postretirement benefits, net of tax													0
Balance at Sep. 26, 2020								41,962	442,648	11,369	(21,370)	0	474,609
Balance at Jun. 27, 2020								41,862	439,943	18,015	(33,062)	0	466,758
Net income (loss)								0	0	(6,646)	0	0	(6,646)
Changes in cumulative translation adjustment								0	0	0			11,692
Changes in cumulative translation adjustment, attributable to parent											11,692		11,692
Changes in cumulative translation adjustment, attributable to non-controlling interest												0
Exercise of stock options								6	80	0	0	0	86
Shares issued for restricted stock units vested								127	(127)	0	0	0	0
Repurchase and retirement of stock								(33)	(547)	0	0	0	(580)
Share-based compensation expense								0	3,299	0	0	0	3,299
Adjustments related to postretirement benefits, net of tax													0
Balance at Sep. 26, 2020								$ 41,962	$ 442,648	$ 11,369	$ (21,370)	$ 0	$ 474,609

[1] Cumulative effect of accounting change relates to our adoption of ASU 2016-02. Please refer to Note 1 of the Condensed Consolidated Financial Statements for further detail on the adoption of this accounting standard.