Revenue - Narrative (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) supplyAgreement	Dec. 31, 2020 USD ($)
Disaggregation of Revenue [Line Items]
Revenue	$ 456,255,000	$ 417,639,000
Number of supply agreements | supplyAgreement	2
Revenue recognized upon satisfaction of performance obligations	$ 47,200,000	30,800,000
Contract liabilities	1,819,000	47,960,000
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue	415,700,000	370,700,000
Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue	40,600,000	46,900,000
6.0 Liter Engines
Disaggregation of Revenue [Line Items]
Revenue	103,700,000
Contract liabilities	$ 0	$ 46,400,000