Restructuring - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended				6 Months Ended		12 Months Ended
	Jul. 15, 2021	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2020
Cost of Sales [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring charge, employee severance							$ 0.4
Selling, General and Administrative Expense [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring charge, employee severance							0.3
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		$ 0.1				$ 0.1
Automotive Racing Market Segment [Member] | Cost of Sales [Member]
Restructuring Cost And Reserve [Line Items]
Non-cash restructuring charge			2.8
Automotive Racing Market Segment [Member] | Selling, General and Administrative Expense [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring charge, employee severance			$ 0.6
Fayetteville, Arkansas Manufacturing Facility [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring severance accrual		0.2				0.2
Relocation costs		$ 0.7		$ 1.8		$ 1.5
Additional charges to cost of sales								$ 3.3
Sale price	$ 7.6
Amount deposited to escrow	$ 0.5
Fayetteville, Arkansas Manufacturing Facility [Member] | Cost of Sales [Member]
Restructuring Cost And Reserve [Line Items]
Non-cash restructuring charge					$ 13.0