Roll-forward of Fair Value of Level 3 Instruments (significant unobservable inputs) (Parenthetical) (Detail) - USD ($) $ in Thousands |
3 Months Ended | ||
|---|---|---|---|
Jun. 30, 2016 |
Sep. 30, 2016 |
Dec. 31, 2015 |
|
| Fair Value Disclosures [Abstract] | |||
| Reduction in fair value of contingent purchase consideration liability | $ 25,500 | ||
| Contingent purchase consideration | $ 0 | $ 24,661 |