Other Assets (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended			1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 31, 2014	Apr. 30, 2014
Other Assets [Line Items]
Amortization expense of other assets	$ 35,986	$ 30,045	$ 25,131
Future amortization expense, 2015	12,315
Future amortization expense, 2016	12,087
Future amortization expense, 2017	11,491
Future amortization expense, 2018	11,191
Future amortization expense, 2019	$ 10,036
Olefins [Member]
Other Assets [Line Items]
Number of years forecasted to test for impairment of goodwill				9 years
Rate used to discount future cash flows for goodwill impairment test				8.80%
Percentage future cash flows of segment could decrease by and not be impaired				10.00%
Vinyls [Member]
Other Assets [Line Items]
Rate used to discount future cash flows for goodwill impairment test					11.50%
Percentage future cash flows of segment could decrease by and not be impaired					10.00%
Minimum [Member]
Other Assets [Line Items]
Discounted cash flow projections period				2015	2014
Maximum [Member]
Other Assets [Line Items]
Discounted cash flow projections period				2023	2023,