Investments in Privately-Held Raw Material Companies - Minority Investment Entities (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) entity	Jun. 30, 2021 USD ($)
Summarized income information of all the minority investment entities that are not consolidated and accounted for under the equity method [Abstract]
Revenue	$ 39,487	$ 33,735	$ 79,140	$ 65,085
Gross profit	15,435	12,238	28,743	23,774
Net income	6,545	4,615	$ 10,517	8,380
Minority investment entities
Impaired entities | entity			1
Five Minority Investments
Summarized income information of all the minority investment entities that are not consolidated and accounted for under the equity method [Abstract]
Revenue	14,099	10,264	$ 24,833	18,789
Gross profit	8,827	5,537	14,827	9,344
Operating income	9,119	4,693	13,268	7,753
Net income	7,253	4,491	10,951	7,103
Minority investment entities
Entity income (loss) excluding impairment	$ 2,200	$ 1,500	$ 3,300	$ 2,600