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Income Taxes (Details) - USD ($) | 6 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2017 | Dec. 31, 2007 | Dec. 31, 2016 | Dec. 31, 2014
Income Tax Disclosure [Abstract] |  |  |  |
Net operating loss carryforwards, regular tax basis | $ 1,200,000,000 |  |  |
Net operating loss carryforwards for computing the alternative minimum tax | 300,000,000 |  |  |
Valuation allowance | 0 |  | $ 0 |
Information regarding income tax examinations [Abstract] |  |  |  |
Amount of IRS assessment for unpaid taxes and penalties related to REMIC issue |  |  |  | $ 197,500,000
Estimate of federal interest that may be due | 195,700,000 |  |  |
Amount of payment made related to the IRS assessment on the REMIC issue |  | $ 65,200,000 |  |
Amount of IRS assessment for unpaid taxes and penalties related to disallowance of carryback of 2009 net operating loss |  |  |  | $ 261,400,000
Estimate of additional state income taxes and interest that may be due | 82,400,000 |  |  |
Total amount of unrecognized tax benefits | 140,800,000 |  |  |
Provision for additional taxes and interest recorded | 27,800,000 |  |  |
Total amount of the unrecognized tax benefits that would affect our effective tax rate | 119,100,000 |  |  |
Unrecognized tax benefits, accrued interest | $ 49,900,000 |  | $ 28,900,000 |

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- Definition The amount of the IRS assessment for unpaid taxes and penalties related to the REMIC issue. + References No definition available. + Details
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- Definition The amount of the IRS assessment for unpaid taxes and penalties related to the disallowance of the carryback of the 2009 net operating loss. + References No definition available. + Details
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- Definition The estimate of additional state income taxes and interest that may be due upon the resolution of the REMIC issue. + References No definition available. + Details
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- Definition The estimate of federal interest that may be due upon the resolution of the REMIC issue. + References No definition available. + Details
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- Definition Amount of operating loss carryforwards, before tax effects, available to reduce future taxable income under enacted tax laws that are used for computing the alternative minimum tax. + References No definition available. + Details
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- Definition The amount of the payment made to the United States Department of Treasury related to the IRS assessment on the REMIC issue. + References No definition available. + Details
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- Definition Amount of deferred tax assets 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 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319 + Details
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- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + 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 (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319 + Details
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- Definition Amount of increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 25 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=96869850&loc=d3e28446-109314 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 25 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=96869850&loc=d3e28511-109314 + Details
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- Definition Amount of unrecognized tax benefits. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + Details
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- Definition Amount of interest expense accrued for an underpayment of income taxes. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319 + Details
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