Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Plan Assets
Defined benefit plan, plan assets, contributions by employer		$ 2,000
Net actuarial loss		49,300	$ 56,500
Expense provision for 401 (k) plans		4,100	4,400	$ 4,300
Company contributions		32,300	41,200	$ 44,800
Hedge fund investments
Pension Plan Assets
Investments in hedge funds which do not have readily determinable fair values		11,600	12,800
Employee Pension Plans
Pension Plan Assets
Defined benefit plan, plan assets, contributions by employer		$ 242	$ 1,235
Discount rate (as a percent)		5.20%	2.70%
Expected return on assets (as a percent)		5.75%	5.75%	5.75%
Employee Pension Plans | Forecast
Pension Plan Assets
Expected return on assets (as a percent)	6.30%