Income Taxes (Tax Carryforwards) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Gross	$ 868,963	$ 878,774
Deferred Tax Assets, Valuation Allowance	18,658	821,429
Deferred Tax Assets, Net of Valuation Allowance	850,305	57,345
Alternative Minimum Tax Credit [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Gross	19,063
Deferred Tax Assets, Valuation Allowance	0
Deferred Tax Assets, Net of Valuation Allowance	19,063
Federal [Member] | Net Operating Loss [Member] | 2023 - 2027 [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Gross	519,755
Deferred Tax Assets, Valuation Allowance	0
Deferred Tax Assets, Net of Valuation Allowance	519,755
Federal [Member] | General Business Tax Credits [Member] | 2028 - 2032 [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Gross	7,799
Deferred Tax Assets, Valuation Allowance	0
Deferred Tax Assets, Net of Valuation Allowance	7,799
State [Member] | Net Operating Loss [Member] | 2023 - 2027 [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Gross	5,296
Deferred Tax Assets, Valuation Allowance	(3,785)
Deferred Tax Assets, Net of Valuation Allowance	1,511
State [Member] | Net Operating Loss [Member] | 2028 - 2032 [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Gross	64,012
Deferred Tax Assets, Valuation Allowance	0
Deferred Tax Assets, Net of Valuation Allowance	64,012
State [Member] | Net Operating Loss [Member] | 2013 - 2017 [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Gross	47
Deferred Tax Assets, Valuation Allowance	0
Deferred Tax Assets, Net of Valuation Allowance	47
State [Member] | Net Operating Loss [Member] | 2018 - 2022 [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Gross	1,828
Deferred Tax Assets, Valuation Allowance	0
Deferred Tax Assets, Net of Valuation Allowance	1,828
State [Member] | Other Credits [Member] | 2013 - 2017 [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Gross	17,565
Deferred Tax Assets, Valuation Allowance	(14,782)
Deferred Tax Assets, Net of Valuation Allowance	2,783
State [Member] | Other Credits [Member] | 2018 - 2022 [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Gross	136
Deferred Tax Assets, Valuation Allowance	(91)
Deferred Tax Assets, Net of Valuation Allowance	$ 45