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Notes Payable, Other and Short-term Borrowings - Carrying Amounts and Estimated Fair Values of Company's Senior Notes (Parenthetical) (Detail) | Mar. 31, 2018 | Dec. 31, 2017 | May 27, 2016
--- | --- | --- | ---
8.125% Senior Notes [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Stated interest rate | 8.125% | 8.125% |
5.375% Senior Notes [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Stated interest rate | 5.375% | 5.375% |
8.375% Senior Notes [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Stated interest rate | 8.375% | 8.375% |
5.125% Senior Notes [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Stated interest rate | 5.125% | 5.125% | 5.125%

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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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