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Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands | 6 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Jun. 30, 2017 | Sep. 30, 2011 | Dec. 31, 2016
Tax Credit Carryforward [Line Items] |  |  |
Tolling Payment Payable to AFG, Gross | $ 2,605 |  | $ 28,691
Income Tax Examination, Penalties and Interest Accrued |  | $ 3,650,000 |
NOL allocated amount | 4,019,178 |  |
AFG [Member] |  |  |
Tax Credit Carryforward [Line Items] |  |  |
NOL allocated amount | 1,386,696 |  |
Percentage Of Notional Federal Tax Liability |  | 50.00% |
U. S. Federal Net Operating Tax [Member] |  |  |
Tax Credit Carryforward [Line Items] |  |  |
NOL allocated amount | 3,931,962 |  |
Capital Loss Carryforward [Member] | United States [Member] |  |  |
Tax Credit Carryforward [Line Items] |  |  |
NOL allocated amount | $ 87,216 |  |
Minimum [Member] |  |  |
Tax Credit Carryforward [Line Items] |  |  |
Operating Loss Carryforwards, Expiration Date | Dec. 31, 2029 |  |
Maximum [Member] |  |  |
Tax Credit Carryforward [Line Items] |  |  |
Operating Loss Carryforwards, Expiration Date | Dec. 31, 2033 |  |

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- Definition The amount of estimated penalties and interest accrued as of the balance sheet date arising from income tax examinations. + 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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