Acquisition of supreme industries, Inc.- Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Sep. 27, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Business Combination, Acquisition Related Costs		$ 0	$ 0	$ 68	$ 0
Finite-Lived Intangible Assets, Amortization Expense, Year Five						$ 19,500
Goodwill		315,977		315,977		317,464
Goodwill, Period Increase (Decrease)				1,500
Revenues		612,690	$ 435,903	1,104,009	$ 798,619
Senior Notes [Member]
Debt Instrument, Face Amount	$ 325,000
Debt Instrument, Interest Rate, Stated Percentage	5.50%
Supreme Industries Inc. [Member]
Business Acquisition, Share Price	$ 21
Business Combination, Acquisition Related Costs				100
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 161,200
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months						20,400
Finite-Lived Intangible Assets, Amortization Expense, Year Two						21,600
Finite-Lived Intangible Assets, Amortization Expense, Year Three						23,100
Finite-Lived Intangible Assets, Amortization Expense, Year Four						$ 24,400
Goodwill	167,714
Revenues		119,500		191,700
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		$ 12,200		$ 14,300
Class A and Class B [Member]
Payments to Acquire Businesses, Gross	360,400
Class A and Class B [Member] | Supreme Industries Inc. [Member]
Payments to Acquire Businesses, Gross	$ 360,400