Income Taxes Operating loss carryforwards (Table Details) $ in Thousands	Dec. 31, 2017 USD ($)
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 882,386
Tax Year 2006 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	8,321
Tax Year 2007 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	62,308
Tax Year 2008 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	53,895
Tax Year 2009 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	512,499
Tax Year 2010 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	92,058
Tax Year 2011 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	45,238
Tax Year 2012 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	33,756
Tax Year 2013 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	30,780
Tax Year 2014 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	7,245
Tax Year 2016 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	17,389
Tax Year 2017 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 18,897