Property, Plant and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 8,304,000	$ 9,028,000	$ 9,833,000
Capital expenditure commitments	$ 2,393,000
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