Fair Value of Performance Units (Detail) - Performance Units Awards $ in Thousands |
6 Months Ended |
---|---|
Jun. 30, 2020
USD ($)
| |
2020 | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |
Fair value at date of grant | $ 826 |
2019 | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |
Fair value at date of grant | 9,958 |
2018 | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |
Fair value at date of grant | 8,004 |
2017 | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |
Fair value at date of grant | 5,780 |
2016 | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |
Fair value at date of grant | $ 3,854 |