Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Components of Net Periodic Benefit Cost
Service cost	$ 313	$ 250	$ 998
Interest cost	326	348	$ 1,393
Net loss	135	53
Net periodic pension cost	$ 774	$ 651