Acquisitions - Additional Information (Detail) $ in Thousands			3 Months Ended		9 Months Ended
	Aug. 10, 2018 USD ($)	Feb. 01, 2018 USD ($) a	Sep. 29, 2018 USD ($)	Sep. 30, 2017 Acquisition	Sep. 29, 2018 USD ($)	Sep. 30, 2017 Acquisition
Business Acquisition [Line Items]
Total cash purchase price					$ 100,787
Number of businesses acquired | Acquisition				0		0
Southern Counties [Member]
Business Acquisition [Line Items]
Date of acquisition	Aug. 10, 2018
Total cash purchase price	$ 65,700
Transaction related costs incurred in acquisition	$ 500
Fore [Member]
Business Acquisition [Line Items]
Date of acquisition		Feb. 01, 2018
Total cash purchase price		$ 35,100
Transaction related costs incurred in acquisition		$ 200
Area of land | a		28
Southern Counties and Fore Acquisition [Member]
Business Acquisition [Line Items]
Actual revenue of the acquired companies			$ 18,800		33,700
Operating income of the acquired companies			$ 2,700		$ 4,600
Southern Counties and Fore Acquisition [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Intangible assets amortization period					3 years
Southern Counties and Fore Acquisition [Member] | Non-competition Agreement [Member]
Business Acquisition [Line Items]
Intangible assets amortization period					5 years
Southern Counties and Fore Acquisition [Member] | Minimum [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets amortization period					7 years
Southern Counties and Fore Acquisition [Member] | Maximum [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets amortization period					15 years