Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities
Net income	$ 174,147	$ 158,506
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	51,844	53,701
Loss from disposition of property, plant and equipment	446	458
Other gains, net	(310)	(181)
Changes in operating assets and liabilities
Accounts receivable—third parties	3,235	(3,821)
Net accounts receivable—Westlake	(8,890)	419
Inventories	955	(402)
Prepaid expenses and other current assets	405	275
Accounts payable	1,207	2,791
Accrued and other liabilities	998	2,096
Other, net	(318)	(170)
Cash flows from investing activities	223,719	213,672
Cash flows from investing activities
Additions to property, plant and equipment	(20,595)	(25,582)
Maturities of investments with Westlake under the Investment Management Agreement	181,000	344,445
Investments with Westlake under the Investment Management Agreement	(190,000)	(336,445)
Other	0	46
Net cash used for investing activities	(29,595)	(17,536)
Cash flows from financing activities
Net proceeds from private placement of common units	0	62,916
Proceeds from debt payable to Westlake	0	123,511
Repayment of debt payable to Westlake	0	(201,445)
Quarterly distributions to noncontrolling interest retained in OpCo by Westlake	(157,248)	(153,766)
Quarterly distributions to unitholders	(33,181)	(29,623)
Net cash used for financing activities	(190,429)	(198,407)
Net increase (decrease) in cash and cash equivalents	3,695	(2,271)
Cash and cash equivalents at beginning of period	19,923	19,744
Cash and cash equivalents at end of period	$ 23,618	$ 17,473