Note 3 - Units Repurchased Pursuant to Repurchase Right and Issued Pursuant to Option Repurchase Plan (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2016
Calculated price for Repurchase Right (in dollars per share)	$ 4.935	$ 7.01
Interim distributions (in dollars per share)	0.375	0.50
Net price paid (in dollars per share)	$ 4.56	$ 6.51
Units repurchased (in shares)	26,774	11,964
Units issued (in shares)	13,387	5,982
Units outstanding following units activity (in shares)	5,587,616	5,601,003	5,587,616