Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities
Net income	$ 80,714	$ 86,028
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	27,698	30,150
Loss (gain) from disposition of property, plant and equipment	567	(127)
Other losses (gains), net	357	(488)
Changes in operating assets and liabilities
Accounts receivable—third parties	(1,239)	(8,753)
Net accounts receivable—Westlake	737	40,010
Inventories	419	(842)
Prepaid expenses and other current assets	153	115
Accounts payable	(2,835)	5,150
Accrued and other liabilities	(487)	7,461
Other, net	138	(9,626)
Cash flows from investing activities	106,222	149,078
Cash flows from investing activities
Additions to property, plant and equipment	(9,679)	(23,168)
Maturities of investments with Westlake under the Investment Management Agreement	112,000	0
Investments with Westlake under the Investment Management Agreement	(110,000)	0
Other	0	1,682
Net cash used for investing activities	(7,679)	(21,486)
Cash flows from financing activities
Proceeds from debt payable to Westlake	3,648	17,000
Repayment of debt payable to Westlake	0	(11,423)
Quarterly distributions to noncontrolling interest retained in OpCo by Westlake	(91,148)	(89,617)
Quarterly distributions to unitholders	(13,071)	(9,478)
Net cash used for financing activities	(100,571)	(93,518)
Net increase (decrease) in cash and cash equivalents	(2,028)	34,074
Cash and cash equivalents at beginning of period	27,008	88,900
Cash and cash equivalents at end of period	$ 24,980	$ 122,974