Segment Information (Total Assets) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Total assets	$ 3,330,047	$ 3,266,821
Olefins [Member]
Segment Reporting Information [Line Items]
Total assets	1,413,225	1,441,752
Vinyls [Member]
Segment Reporting Information [Line Items]
Total assets	862,549	824,825
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Total assets	$ 1,054,273	$ 1,000,244