Summary of Significant Accounting Policies (Other Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Restricted assets	$ 1,551	$ 3,456
Prepaid pension costs	44,585	35,209
Other assets	30,549	26,853
Total other assets	$ 76,685	$ 65,518