Employee Benefits - Components of Net Periodic Pension Cost and Other Changes in Plan Assets and Benefit (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Components of Net Periodic Pension Cost
Interest cost on projected benefit obligation	$ 721	$ 905	$ 2,221	$ 2,686
Expected return on plan assets	(668)	(970)	(2,029)	(2,913)
Net amortization	246	411	792	1,180
Settlement Charge	370	671	1,296	671
Net Periodic Pension Expense	$ 669	$ 1,017	$ 2,280	$ 1,624