Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net income	$ 78,396	$ 80,714
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	26,844	27,698
Loss from disposition of property, plant and equipment	458	567
Other losses (gains), net	(180)	357
Changes in operating assets and liabilities
Accounts receivable—third parties	1,102	(1,239)
Net accounts receivable—Westlake	1,479	737
Inventories	(587)	419
Prepaid expenses and other current assets	119	153
Accounts payable	2,497	(2,835)
Accrued and other liabilities	3,472	(487)
Other, net	(101)	138
Cash flows from investing activities	113,499	106,222
Cash flows from investing activities
Additions to property, plant and equipment	(12,144)	(9,679)
Maturities of investments with Westlake under the Investment Management Agreement	80,000	112,000
Investments with Westlake under the Investment Management Agreement	(207,512)	(110,000)
Other	46	0
Net cash used for investing activities	(139,610)	(7,679)
Cash flows from financing activities
Proceeds from private placement of common units	62,934	0
Proceeds from debt payable to Westlake	123,512	3,648
Quarterly distributions to noncontrolling interest retained in OpCo by Westlake	(81,507)	(91,148)
Quarterly distributions to unitholders	(13,957)	(13,071)
Net cash provided by (used for) financing activities	90,982	(100,571)
Net increase (decrease) in cash and cash equivalents	64,871	(2,028)
Cash and cash equivalents at beginning of period	19,744	27,008
Cash and cash equivalents at end of period	$ 84,615	$ 24,980