Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2016

Summary Of Assets And Liabilities Accounted At Fair Value On A Recurring Basis

The following tables summarize, by level within the fair value hierarchy, the Company's assets and liabilities that were accounted for at fair value on a recurring basis:



	September 30, 2016
	Level 1			Level 2			Total
Derivative instruments
Risk management assets—Commodity forward contracts	$	1,551		$	4,344		$	5,895
Risk management liabilities—Commodity forward contracts	(8,091		)	(1,916		)	(10,007		)

	December 31, 2015
	Level 1			Level 2			Total
Derivative instruments
Risk management assets—Commodity forward contracts	$	5,553		$	—		$	5,553
Risk management liabilities—Commodity forward contracts	(11,648		)	(10,114		)	(21,762		)
Marketable securities
Available-for-sale securities	48,081			520,144			568,225

Summary Of Carrying And Fair Values Of Long-Term Debt

The carrying and fair values of the Company's long-term debt are summarized in the table below. The fair value of the Company's long-term debt instruments is determined using a market approach, based upon quotes from financial reporting services. Because the Company's long-term debt instruments may not be actively traded, the inputs used to measure the fair value of the Company's long-term debt are classified as Level 2 inputs within the fair value hierarchy.



	September 30, 2016				December 31, 2015
	Carrying Value		Fair Value		Carrying Value		Fair Value
Revolving credit facility	$	325,000	$	325,000	$	—	$	—
4.625% Westlake 2021 Senior Notes	653,256		653,715		—		—
4.625% Subsidiary 2021 Senior Notes	66,243		66,058		—		—
3.60% senior notes due 2022	248,024		251,480		247,768		244,828
4.875% Westlake 2023 Senior Notes	447,751		454,151		—		—
4.875% Subsidiary 2023 Senior Notes	16,769		16,954		—		—
3.60% 2026 Senior Notes	739,082		752,055		—		—
Loan related to tax-exempt waste disposal revenue bonds due 2027	10,889		10,889		10,889		10,889
6 ½% senior notes due 2029	99,066		117,726		99,011		117,153
6 ¾% senior notes due 2032	248,087		265,383		247,998		268,490
6 ½% 2035 GO Zone Senior Notes	88,149		105,298		88,116		106,491
6 ½% 2035 IKE Zone Senior Notes	64,390		76,837		64,366		76,741
5.0% 2046 Senior Notes	673,879		705,985		—		—