Employee Benefit Plans (Net Benefit Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits, Description [Abstract]
Service cost	$ 14,279	$ 12,767	$ 16,154
Interest cost	34,197	37,260	34,733
Expected return on assets	(65,689)	(62,590)	(60,296)
Amortization of prior service cost	0	(57)	(79)
Amortization of net actuarial loss	25,324	10,924	13,902
Total pension expense	8,111	(1,582)	4,572
Current year actuarial gain (loss)	(55,023)	20,049	32,012
Total change from defined benefit plans, net of tax	(80,347)	9,068	18,031
Total recognized in net periodic benefit cost and other comprehensive income	$ (72,236)	$ 7,486	$ 22,603