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Indebtedness - Debt Costs - Additional Information (Detail) - USD ($) $ in Millions | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016
--- | --- | --- | --- | ---
Debt [Line Items] |  |  |  |
Reduction of debt | $ 6.9 |  |  | $ 6.8
Minimum |  |  |  |
Debt [Line Items] |  |  |  |
Interest coverage ratio | 300.00% | 300.00% | 300.00% |
Maximum |  |  |  |
Debt [Line Items] |  |  |  |
Debt to capital ratio | 0.55 |  |  |

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- Definition Reduction of debt. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Indebtedness divided by net capital. + References No definition available. + Details
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