Long-Term Borrowings - Components of Long-term Borrowings (Detail) - USD ($) $ in Thousands |
Jun. 30, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Debt Instrument [Line Items] | ||
| Less: unamortized discount and debt issuance costs | $ (8,870) | $ (3,918) |
| Long-term borrowings, net of unamortized discount and debt issuance costs | 302,380 | 221,082 |
| Exchangeable Senior Notes [Member] | 5.0% Exchangeable Senior Notes due March 2021 [Member] | ||
| Debt Instrument [Line Items] | ||
| Long-term borrowings | 86,250 | |
| Senior Notes [Member] | 6.625% Senior Notes Due 2021 [Member] | ||
| Debt Instrument [Line Items] | ||
| Long-term borrowings | $ 225,000 | $ 225,000 |