Income Taxes (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
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	1.20%	0.90%	1.20%	0.90%
Domestic production activities deduction	(1.70%)	(1.40%)	(1.80%)	(1.90%)
Noncontrolling interest in partially-owned subsidiaries	(0.90%)	(1.00%)	(0.90%)	(1.10%)
State adjustments	0.00%	1.10%	0.10%	0.30%
Other, net	0.00%	(1.40%)	0.10%	(0.40%)
Effective rate	33.60%	33.20%	33.70%	32.80%