Income Taxes - Schedule of Reconciliation of U.S. Statutory Income Tax Rate to Company's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes
U.S. statutory tax rate	35.00%	35.00%	34.00%
Increase due to state and local taxes, net of federal benefit	2.60%	2.60%	2.60%
Effect of permanent differences	1.00%	0.60%	1.20%
Income attributable to non-controlling interests	(19.60%)	(19.80%)	(28.70%)
Effective tax rate	19.00%	18.40%	9.10%