Income Taxes - Effective rate reconciliation (Details)	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reconciliation between the statutory United States Federal income tax rate and the Company's effective income tax rate
Statutory rate	35.00%	35.00%	35.00%	35.00%
State taxes	1.40%	1.30%	1.40%	1.20%
Noncontrolling interest in partially-owned subsidiaries	(1.40%)	(0.80%)	(0.90%)	(1.00%)
Settlements with tax authorities	(0.00%)	(0.00%)	(2.10%)	(0.00%)
Equity compensation	(0.20%)	0.00%	0.80%	0.00%
Other, net	2.10%	0.30%	1.80%	0.40%
Effective rate	36.90%	35.80%	36.00%	35.60%

Effective Income Tax Reconciliation, Equity Compensation

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to noncontrolling interest income (loss) exempt from income taxes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Topic 740
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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