Debt - Narrative (Details)	Apr. 20, 2022 USD ($)	Mar. 25, 2022 USD ($) agreement day	Dec. 10, 2021 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)
Debt Instrument [Line Items]
Short-term financing				$ 209,820,000	$ 155,000,000
Debt instrument, number of loan agreements amended | agreement		2
Debt, long-term and short-term, combined amount				210,600,000
Cash and cash equivalents				3,448,000	6,255,000	$ 5,503,000
Revolving credit facility
Debt Instrument [Line Items]
Short-term financing				130,000,000	130,000,000
First, Second, And Fourth Shareholder's Loan Agreement, Weichai
Debt Instrument [Line Items]
Debt instrument, incremental borrowing cost	1.00%
Accrued unpaid interest				2,200,000	$ 600,000
First, Second, And Fourth Shareholder's Loan Agreement, Weichai | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread on variable rate	4.65%
First Shareholder's Loan Agreement, Weichai | Revolving credit facility
Debt Instrument [Line Items]
Short-term financing				0
Second Shareholder's Loan Agreement, Weichai | Revolving credit facility
Debt Instrument [Line Items]
Short-term financing				25,000,000
Third Shareholder's Loan Agreement, Weichai | Revolving credit facility
Debt Instrument [Line Items]
Short-term financing				50,000,000
Fourth Shareholder's Loan Agreement, Weichai | Revolving credit facility
Debt Instrument [Line Items]
Short-term financing				4,800,000
Revolving credit facility | Second Standard Chartered Bank Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 130,000,000
Number of days to submit borrowing request | day		5
Short-term financing				130,000,000
Basis spread on variable rate		2.95%
Revolving credit facility | First Shareholder's Loan Agreement, Weichai
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 130,000,000		130,000,000
Revolving credit facility | Second Shareholder's Loan Agreement, Weichai
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 25,000,000		25,000,000
Revolving credit facility | Third Shareholder's Loan Agreement, Weichai
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 50,000,000	50,000,000
Revolving credit facility | Third Shareholder's Loan Agreement, Weichai | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate			4.50%
Revolving credit facility | Fourth Shareholder's Loan Agreement, Weichai
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 30,000,000			$ 30,000,000