Condensed 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]			$ 10,352			$ 10,352
Balance at Dec. 29, 2018								$ 40,763	$ 419,690	$ 111,670	$ (25,880)	$ (299)	$ 545,944
Net income (loss)										(22,687)			(22,687)
Changes in cumulative translation adjustment													(5,262)
Changes in cumulative translation adjustment, attributable to parent											(5,258)		(5,262)
Changes in cumulative translation adjustment, attributable to non-controlling interest												(4)
Adjustments related to postretirement benefits, net of tax											474		474
Cash dividends - $0.06 per share										(2,450)			(2,450)
Exercise of stock options								10	68				78
Shares issued for restricted stock units vested								365	(365)
Repurchase and retirement of stock								(123)	(1,705)				(1,828)
Noncontrolling interest										53		(53)
Share-based compensation expense									3,693				3,693
Balance at Mar. 30, 2019								41,015	421,381	96,938	(30,664)	(356)	528,314
Balance at Dec. 28, 2019								41,395	433,190	42,517	(34,030)		483,072
Net income (loss)										(17,276)			(17,276)
Changes in cumulative translation adjustment											(929)		(929)
Changes in cumulative translation adjustment, attributable to parent													(929)
Adjustments related to postretirement benefits, net of tax
Cash dividends - $0.06 per share										(2,486)			(2,486)
Exercise of stock options								22	267				289
Shares issued for restricted stock units vested								403	(403)
Repurchase and retirement of stock								(134)	(1,263)				(1,397)
Share-based compensation expense									3,611				3,611
Balance at Mar. 28, 2020								$ 41,686	$ 435,402	$ 22,755	$ (34,959)		$ 464,884

[1] Cumulative effect of accounting change relates to our adoption of ASU 2014-09.