Equity Investments - Northstar New Jersey (Details) - Northstar NJ - USD ($) $ in Millions	1 Months Ended	6 Months Ended		12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Incentive compensation cap, percentage of net income				3.00%
Investee payment to third party cap, percentage of net income				2.00%
Investee payment to third party, shortfall credit		$ 20.0
Investee payment to third party	$ 15.4
Contribution to investee	$ 2.7
Shortfall payment			$ 5.9