Employee Benefits - Components of Net Periodic Pension Cost and Other Changes in Plan Assets and Benefit (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Components of Net Periodic Pension Cost
Interest cost on projected benefit obligation	$ 890	$ 989	$ 1,781	$ 1,978
Expected return on plan assets	(971)	(1,181)	(1,943)	(2,361)
Net amortization	385	395	769	789
Net Periodic Pension Expense	$ 304	$ 203	$ 607	$ 406