Income Taxes Effective Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Tax provision at statutory rate, Percent	21.00%	35.00%	35.00%
Effect of foreign operations, Percent	4.80%	(1.10%)	4.30%
Foreign valuation allowance, Percent	0.00%	(0.30%)	2.90%
Foreign goodwill impairment, Percent	0.00%	0.00%	2.40%
Effect of foreign tax rate change, Percent	0.00%	0.00%	(2.00%)
Effect of U.S. transition (toll) tax, Percent	0.50%	7.20%	0.00%
Effect of U.S. federal rate change, Percent	0.00%	(133.30%)	0.00%
State income taxes, net of federal income tax benefit, Percent	3.00%	3.80%	4.10%
Benefit of track maintenance credit, Percent	(9.90%)	(0.00%)	(13.40%)
Other, net, Percent	0.80%	0.30%	1.20%
Effective Income Tax Rate, Percent	20.20%	(88.40%)	34.50%