Employee Benefits - Future Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Future payments under the Plan
2020	$ 1,913
2021	1,913
2022	1,913
2023	1,913
2024	1,913
Thereafter	9,649
Total	$ 19,214	$ 18,927	$ 20,793	$ 21,304