Income Taxes - Reconciliation between the statutory U.S. Federal income tax rate and the Company's effective income tax rate (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory rate	21.00%	35.00%	35.00%
Effect of Tax Cuts and Jobs Act	(3.90%)	(243.70%)	(0.00%)
State taxes	2.30%	(1.90%)	1.20%
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Percent	2.90%	0.00%	0.00%
Noncontrolling interest in partially-owned subsidiaries	0.50%	2.00%	(2.40%)
Settlements with tax authorities	(0.00%)	2.10%	(0.10%)
Equity compensation	(1.40%)	0.80%	0.00%
Changes in valuation allowances and reserves	1.60%	1.90%	(1.20%)
Effective Tax Rate Reconciliation, Interest Rate Limitations	1.30%	0.00%	0.00%
Effective income tax rate reconciliation, changes in state tax laws, percent	5.20%	(0.50%)	1.40%
Other, net	(0.40%)	0.30%	0.60%
Effective rate	28.10%	(212.20%)	34.50%