Goodwill and Purchased Intangible Assets - Details of Purchased Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 23, 2016	Dec. 25, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 63,657	$ 63,657
Accumulated Amortization	(25,193)	(20,875)
Carrying Value	38,464	42,782
American Integration Technologies LLC [Member] \| Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	19,000	19,000
Accumulated Amortization	(16,618)	(15,298)
Carrying Value	2,382	$ 3,702
Useful Life (in years)		7 years
American Integration Technologies LLC [Member] \| Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,900	$ 1,900
Accumulated Amortization	(1,900)	$ (1,900)
Useful Life (in years)		6 years
American Integration Technologies LLC [Member] \| Intellectual Properties/Know-How [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,600	$ 1,600
Accumulated Amortization	(971)	(800)
Carrying Value	629	$ 800
Useful Life (in years)		7 years
Marchi Thermal Systems Inc [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	23,370
Marchi Thermal Systems Inc [Member] \| Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	9,900	$ 9,900
Accumulated Amortization	(1,650)	(907)
Carrying Value	$ 8,250	$ 8,993
Useful Life (in years)	10 years	10 years
Marchi Thermal Systems Inc [Member] \| Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,170	$ 1,170
Accumulated Amortization	(387)	(217)
Carrying Value	$ 783	$ 953
Useful Life (in years)	6 years	6 years
Marchi Thermal Systems Inc [Member] \| Intellectual Properties/Know-How [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 12,300	$ 12,300
Accumulated Amortization	(2,298)	(1,264)
Carrying Value	$ 10,002	$ 11,036
Marchi Thermal Systems Inc [Member] \| Intellectual Properties/Know-How [Member] \| Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (in years)	8 years	8 years
Marchi Thermal Systems Inc [Member] \| Intellectual Properties/Know-How [Member] \| Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life (in years)	12 years	12 years
Miconex [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 8,800
Miconex [Member] \| Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,800	$ 8,800
Accumulated Amortization	(1,369)	(489)
Carrying Value	$ 7,431	$ 8,311
Useful Life (in years)	7 years 6 months	7 years 6 months
UCT [Member] \| Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 8,987	$ 8,987
Carrying Value	$ 8,987	$ 8,987

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
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- Definition

The amount of identifiable intangible assets recognized as of the acquisition date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 805
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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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