Other Financial Statement Information - Property, Plant and Equipment - Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment - Gross	$ 261,682	$ 261,205
Less accumulated depreciation	(157,074)	(152,607)
Property, plant and equipment - Net	104,608	108,598
Land and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment - Gross	12,631	13,141
Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment - Gross	75,038	75,941
Machinery, Equipment and Aircraft [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment - Gross	169,620	166,999
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment - Gross	$ 4,393	$ 5,124