Incentive Plans - Summary of Impact of LFI and Other Similar Deferred Compensation Arrangements (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
---|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
|
Share Based Compensation [Abstract] | ||||
Amortization, net of forfeitures | $ 36,293 | $ 28,310 | $ 52,129 | $ 41,293 |
Change in the fair value of underlying investments | (499) | 5,753 | (1,935) | 13,106 |
Total | $ 35,794 | $ 34,063 | $ 50,194 | $ 54,399 |