Income Taxes - Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of federal statutory tax rate with effective tax rate
Federal statutory tax rate	21.00%	35.00%	35.00%
Impact of one-time deemed repatriation	6.40%	10.70%	0.00%
Impact on deferred taxes for changes in tax rates	(3.50%)	(196.40%)	(0.10%)
Additional deferred tax adjustments	(1.60%)	0.00%	0.00%
State income taxes, net of federal income tax benefit	3.80%	3.00%	4.00%
Foreign rates varying from federal statutory tax rate	0.10%	(4.00%)	(3.30%)
Tax contingencies	(1.10%)	(0.30%)	(0.20%)
Other, net	1.20%	0.10%	(0.50%)
Effective tax rate	26.30%	(151.90%)	34.90%