v3.8.0.1

Condensed Consolidating Financial Information - Additional Information (Detail) - USD ($) | Sep. 30, 2017 | Mar. 17, 2014
--- | --- | ---
Supplemental Guarantor Financial Information [Line Items] |  |
Ownership percentage in domestic subsidiaries | 100.00% |
5.25% Senior Notes due March 15, 2019 [Member] | Senior Notes [Member] |  |
Supplemental Guarantor Financial Information [Line Items] |  |
Senior notes, amount issued |  | $ 500,000,000
Interest rate on Senior Notes | 5.25% | 5.25%

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