Employee Benefit Plans (Net Benefit Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits, Description [Abstract]
Service cost	$ 12,767	$ 16,154	$ 15,186
Interest cost	37,260	34,733	35,593
Expected return on assets	(62,590)	(60,296)	(53,244)
Amortization of prior service cost	(57)	(79)	(210)
Amortization of net actuarial loss	10,924	13,902	9,510
Total pension expense	(1,582)	4,572	7,255
Current year actuarial gain (loss)	(20,049)	(32,012)	(12,945)
Total change from defined benefit plans, net of tax	9,068	18,031	3,225
Total recognized in net periodic benefit cost and other comprehensive income	$ 7,486	$ 22,603	$ 10,480