Restructuring - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 625	$ 1,306	$ 2,062	$ 2,886
Corporate Service Center, Severance
Restructuring Cost and Reserve [Line Items]
Restructuring expenses		$ 900
Wood Mobile Office Business Divesture
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			800
Evergreen Tank Solutions Integration
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			$ 1,300