INCOME TAXES - Net Operating Loss Carryforwards and Unrecognized Tax Benefits (Details 4) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016
Income taxes
Valuation allowance	$ 0
Decrease in valuation allowance	100,000
Gross deferred tax assets related to net operating loss carryforwards	1,500,000
Deferred tax liability related to investment in joint venture	$ 1,349,000	$ 0
Unrecognized tax benefits		0
State
Income taxes
Operating loss carryforwards		2,600,000
U.S. Federal
Income taxes
Operating loss carryforwards		1,100,000
U.S. Federal | Minimum tax credit carryforwards
Income taxes
Tax credit amount		$ 200,000