Other Assets (Goodwill) (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Oct. 31, 2015	Apr. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Impairment since goodwill was initially recorded			$ 0
Goodwill			62,016	$ 62,016	$ 62,016
Goodwill, Other Changes			0
Goodwill, Acquired During Period				0
Olefins [Member]
Goodwill [Line Items]
Goodwill			29,990	29,990	29,990
Goodwill, Other Changes			0
Goodwill, Acquired During Period				0
Vinyls [Member]
Goodwill [Line Items]
Goodwill			32,026	32,026	$ 32,026
Goodwill, Other Changes			$ 0
Goodwill, Acquired During Period				$ 0
Minimum [Member]
Goodwill [Line Items]
Discounted cash flow projections period	2016	2015
Maximum [Member]
Goodwill [Line Items]
Discounted cash flow projections period	2024	2023,