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Income Taxes - Reconciliation of U.S. Federal Statutory Tax Rate to Company's Effective Tax Rate (Details)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income tax provision
Statutory U.S. federal tax rate		21.00%	21.00%	35.00%
State income taxes, net of federal benefit		3.50%	3.70%	2.70%
Foreign operations		(471.20%)	1.30%	(5.40%)
Compensation plans		240.60%	1.60%	(0.70%)
Changes in tax laws		0.00%	0.00%	(25.20%)
Changes in valuation allowances		(107.20%)	0.00%	0.30%
Unrecognized tax benefits		420.40%	0.50%	0.50%
Affiliate divestments		(120.40%)	0.00%	0.00%
Reduction in carrying value of Affiliates		0.00%	13.00%	0.00%
Changes in U.S. tax provision to return		(195.70%)	(1.00%)	0.00%
Other		72.00%	0.90%	(0.40%)
Effective tax rate (controlling interest)		(137.00%)	41.00%	6.80%
Non-Controlling Interests
Income tax provision
Effect of income from non-controlling interests		137.90%	(15.60%)	(1.30%)
Controlling interests
Income tax provision
Effective tax rate (controlling interest)	[1]	(137.00%)	41.00%	6.80%
Effective tax rate		0.90%	25.40%	5.50%
[1] Taxes attributable to the controlling interest divided by Income before income taxes (controlling interest).

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A ratio calculated by dividing the amount of income tax expense attributable to the controlling interest by pretax income from continuing operations attributable to the controlling interest.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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