Restructuring - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended			6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Automotive Racing Market Segment [Member]
Restructuring Cost And Reserve [Line Items]
Non-cash restructuring charge	$ 3.4
Restructuring charge, write-down of after-market inventory to salvage value	1.3
Restructuring charge, employee severance	1.0			$ 0.7
Restructuring charges, contract terminations costs	0.5
Restructuring severance accrual				1.1	$ 1.1
Automotive Racing Market Segment [Member] | Cost of Sales [Member]
Restructuring Cost And Reserve [Line Items]
Non-cash restructuring charge	2.8
Restructuring charge, employee severance				0.4
Automotive Racing Market Segment [Member] | Selling, General and Administrative Expense [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring charge, employee severance	$ 0.6			0.3
Fayetteville, Arkansas Manufacturing Facility [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring charge, employee severance			$ 1.6
Restructuring severance accrual				$ 0.3	0.3
Accelerated depreciation			7.6			$ 7.6
Restructuring charge, write-down of inventory to net salvage value			3.2
Restructuring charge, accelerated amortization of right of use assets			0.6
Relocation costs		$ 1.8			2.9
Additional other costs					$ 0.4
Fayetteville, Arkansas Manufacturing Facility [Member] | Cost of Sales [Member]
Restructuring Cost And Reserve [Line Items]
Non-cash restructuring charge			$ 13.0