Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities
Net income	$ 158,506	$ 165,190
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	53,701	55,284
Loss from disposition of property, plant and equipment	458	567
Other losses (gains), net	(181)	538
Changes in operating assets and liabilities
Accounts receivable—third parties	(3,821)	1,284
Net accounts receivable—Westlake	419	2,885
Inventories	(402)	(538)
Prepaid expenses and other current assets	275	260
Accounts payable	2,791	(4,836)
Accrued and other liabilities	2,096	27
Other, net	(170)	(90)
Cash flows from investing activities	213,672	220,571
Cash flows from investing activities
Additions to property, plant and equipment	(25,582)	(16,620)
Maturities of investments with Westlake under the Investment Management Agreement	344,445	178,000
Investments with Westlake under the Investment Management Agreement	(336,445)	(185,000)
Other	46	251
Net cash used for investing activities	(17,536)	(23,369)
Cash flows from financing activities
Net proceeds from private placement of common units	62,916	0
Proceeds from debt payable to Westlake	123,511	3,648
Repayment of debt payable to Westlake	(201,445)	0
Quarterly distributions to noncontrolling interest retained in OpCo by Westlake	(153,766)	(172,758)
Quarterly distributions to unitholders	(29,623)	(26,617)
Net cash used for financing activities	(198,407)	(195,727)
Net increase (decrease) in cash and cash equivalents	(2,271)	1,475
Cash and cash equivalents at beginning of period	19,744	27,008
Cash and cash equivalents at end of period	$ 17,473	$ 28,483