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Property, Plant and Equipment - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 30, 2016
Dec. 31, 2015
Property, Plant and Equipment [Line Items]      
Depreciation expense $ 8,763,000 $ 8,304,000 $ 9,028,000
Capital expenditure commitments $ 1,911,000    
Maximum [Member]      
Property, Plant and Equipment [Line Items]      
Depreciation and amortization period 39 years    
Minimum [Member]      
Property, Plant and Equipment [Line Items]      
Depreciation and amortization period 3 years