Segment Information (Total Assets) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 5,126,283	$ 4,060,909
Olefins
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,740,878	1,557,510
Vinyls
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,898,250	1,740,595
Corporate and Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 487,155	$ 762,804