Related Party Transactions Related Party Transactions (Receivable under the Investment Management Agreement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
IMA, Partnership earned amount added to market rate, basis points	five
Receivable under the Investment Management Agreement—Westlake Corporation ("Westlake")	$ 64,996	$ 106,243
Westlake | Affiliated Entity
Related Party Transaction [Line Items]
Interest earned related to the IMA	1,875	296	$ 932
Westlake | Accounts Receivable | Affiliated Entity
Related Party Transaction [Line Items]
Accrued interest included in receivable under IMA	$ 940	$ 71