Income Taxes (Valuation Allowance on Deferred Tax Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Federal net operating loss carryforwards	$ 308,738	$ 312,113
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Total net operating losses	912,700
Operating loss carryforwards, valuation allowance	200,500
Internal Revenue Service (IRS) \| General Business Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	10,700
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Federal net operating loss carryforwards	653,500
Operating loss carryforwards, valuation allowance	$ 47,300

Net Operating Loss, Total

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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The portion of the valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from net operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 30
-Paragraph 5
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=6907311&loc=d3e30536-109315

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

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The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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