Other Comprehensive Income (Loss) - Reclassification out of Accumulated Other Comprehensive Income (Details) - Reclassification out of Accumulated Other Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Total	$ 1,930	$ 632	$ 529
Amortization of prior service, net actuarial loss, and other
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Total	1,694	372	291
Net settlement loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Total	$ 236	$ 260	$ 238