Summary of significant accounting policies.

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Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.14)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.13)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(14))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(8))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

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Summary of Significant Accounting Policies - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Summary Of Significant Accounting Policies [Line Items]
Total, at cost	$ 1,587,817	$ 1,405,997
Accumulated depreciation	(732,278)	(677,076)
Property and equipment, net	855,539	728,921	$ 663,527
Land
Summary Of Significant Accounting Policies [Line Items]
Total, at cost	124,654	112,267
Buildings and Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Total, at cost	$ 662,753	597,387
Buildings and Improvements [Member] \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Life	15 years
Buildings and Improvements [Member] \| Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Life	50 years
Machinery Equipment and Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Total, at cost	$ 800,410	$ 696,343
Machinery Equipment and Software [Member] \| Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Life	3 years
Machinery Equipment and Software [Member] \| Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Life	10 years