Long-term Debt, Collateralized and Short-Term Borrowings - Notes Payable, Collateralized and Short-Term Borrowings (Parenthetical) (Detail) |
Dec. 31, 2017 |
Dec. 31, 2016 |
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% |