Note 3 - Segment Reporting Information (Details Textual) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2015
Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | Phillips 66 [Member]
Concentration Risk, Percentage				10.00%
Revenue, Net				$ 17,045,000
Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Concentration Risk, Percentage		0.00%	0.00%		0.00%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Phillips 66 [Member]
Concentration Risk, Percentage				11.00%
Accounts, Notes, Loans and Financing Receivable, Net, Current		$ 4,690,000		$ 4,690,000
Accounts Receivable [Member] | Customer Concentration Risk [Member]
Concentration Risk, Percentage						0.00%
CANADA
Number of Operating Segments				1
Revenue, Net	[1]				$ 41,000
Number of Operating Segments				3
Revenue, Net	[1]	84,687,000	$ 84,715,000	$ 170,612,000	$ 163,181,000
Accounts, Notes, Loans and Financing Receivable, Net, Current		$ 43,122,000		$ 43,122,000		$ 43,661,000
Intersegment Revenue Markup Percentage				10.00%

[1] Net sales are attributed to geographic areas based upon the location of the operation making the sale.