Income Taxes - Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Effective income tax rate reconciliation [Abstract]
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%
U.S. state and local income taxes, net of federal income tax benefit	2.20%	2.20%	2.20%
Income of pass-through entities allocated to non-controlling interests	(5.40%)	(6.20%)	(6.30%)
Section 199 - Domestic Production Activities deduction	(2.50%)	(2.30%)	(2.40%)
Other	1.30%	0.60%	2.60%
Effective income tax rate	30.60%	29.30%	31.10%