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Related Party Transactions (Accounts Receivable from and Accounts Payable to Related Parties) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
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")	$ 104,529		$ 134,557
Affiliated Entity
Related Party Transaction [Line Items]
Accounts receivable, net—Westlake	55,051		31,975
Accounts payable	42,628		20,744
Affiliated Entity \| Westlake
Related Party Transaction [Line Items]
Interest earned related to the IMA	1,357	$ 1,305
Affiliated Entity \| Westlake \| Accounts Receivable
Related Party Transaction [Line Items]
Accrued interest included in receivable under IMA	$ 1,357		$ 1,385