Segment Information (Total Assets) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 3,923,449	$ 3,412,196
Olefins
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,560,303	1,439,308
Vinyls
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,577,549	1,030,912
Corporate and Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 785,597	$ 941,976