Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax liabilities:
Property, plant and equipment and Rail assets leased to others	$ (203,432)	$ (149,317)
Deferred Tax Liabilities, Intangible Assets	(9,677)	(13,736)
Investments	(50,244)	(41,354)
Other	(7,878)	(10,228)
Deferred tax liabilities	(271,231)	(214,635)
Deferred tax assets:
Employee benefits	20,910	20,583
Accounts and notes receivable	4,207	3,577
Inventory	1,905	2,437
Federal income tax credits	25,163	12,005
Deferred interest	359	2,385
Net operating loss carryforwards	25,427	5,259
Derivatives instruments	5,949	3,123
Lease liability	9,068	11,072
Other	9,548	8,970
Total deferred tax assets	102,536	69,411
less: Valuation allowance	(1,452)	(931)
Net deferred tax assets	101,084	68,480
Net deferred tax liabilities	$ (170,147)	$ (146,155)