Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Components of Net Periodic Benefit Cost
Service cost	$ 351	$ 313	$ 1,254
Interest cost	319	326	$ 1,306
Net loss	197	135
Net periodic pension cost	$ 867	$ 774