Unit-based Compensation (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) director $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Jul. 15, 2014 shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	8 months 23 days
Phantom Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Beginning balance	19,677	29,264
Granted	18,272	9,777
Vested	(24,315)	(19,364)
Ending balance	13,634	19,677	29,264
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Fair Value, beginning balance (usd per share) | $ / shares	$ 23.78	$ 23.09
Weighted Average Grant Date Fair Value, Granted (usd per share) | $ / shares	22.03	26.00
Weighted Average Grant Date Fair Value, Vested (usd per share) | $ / shares	21.90	25.20
Weighted Average Fair Value, ending balance (usd per share) | $ / shares	$ 23.24	$ 23.78	$ 23.09
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	4,638
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value | $	$ 532
Westlake Chemical Partners LP Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Number of units authorized				1,270,000
Total units available for grant	1,237,369
Unrecognized compensation cost | $	$ 251
Westlake Chemical Partners LP Long-Term Incentive Plan [Member] | Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Total compensation cost | $	$ 387	$ 363	$ 289
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Deferred Compensation Arrangement with Individual, Number of Directors That Retired in Period | director	1