Income Taxes - Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation:
Income tax expense (benefit) at federal statutory rate	35.00%	35.00%	35.00%
State and local income taxes net of federal tax benefit			(43.00%)
Noncontrolling interest and nontaxable income	(33.20%)	(37.40%)
Tax Cuts and Jobs Act of 2017	30.70%
Nondeductible/nontaxable items	1.20%	2.40%	8.00%
Income tax expense (benefit)	33.70%