Debt (Write-off of Senior Note Issuance Costs Discount and Premium) (Detail) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2017 |
Mar. 31, 2016 |
|
| Debt Disclosure [Abstract] | ||
| Write-off of Senior Note issuance costs, discount and premium | $ 0 | $ 16,970 |