Goodwill - Change in Carrying Amount of Goodwill (Detail) - USD ($) |
3 Months Ended | 6 Months Ended | 8 Months Ended | 12 Months Ended |
|---|---|---|---|---|
Mar. 31, 2015 |
Jun. 30, 2015 |
Sep. 01, 2015 |
Dec. 31, 2016 |
|
| Goodwill [Roll Forward] | ||||
| Beginning Balance | $ 20,899,000 | |||
| Impairment of goodwill | $ 0 | $ 0 | $ 0 | (20,899,000) |
| Ending Balance | $ 0 |