Goodwill and Intangible Assets - Intangible Assets (Detail) - USD ($) $ in Thousands |
12 Months Ended | |
---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
Finite-Lived Intangible Assets [Line Items] | ||
Net intangible assets | $ 184,468 | $ 82,511 |
Customer relationships | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross intangible assets | 199,265 | 118,223 |
Accumulated amortization | (54,757) | (38,429) |
Net intangible assets | $ 144,508 | $ 79,794 |
Weighted average useful life | 11 years | 14 years |
Other Intangibles | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross intangible assets | $ 43,537 | $ 4,045 |
Accumulated amortization | (3,577) | (1,328) |
Net intangible assets | $ 39,960 | $ 2,717 |
Weighted average useful life | 7 years | 5 years |