Note 2 - Sales of Subsidiary; Discontinued Operations (Details Textual) - USD ($)	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Chem Free [Member] | Discontinued Operations, Disposed of by Sale [Member] | Restricted Cash and Cash Equivalents after Working Capital Adjustment [Member]
Restricted Cash and Cash Equivalents, Current						$ 880,000
Chem Free [Member] | Discontinued Operations, Disposed of by Sale [Member]
Disposal Group, Including Discontinued Operation, Consideration			$ 21,600,000
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			18,746,000
Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities	$ 120,000			$ 120,000		120,000
Increase in Restricted Cash			$ 3,300,000
Restricted Cash and Cash Equivalents, Current	2,200,000			2,200,000
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax		$ (20,000)			$ 18,726,000	18,726,000
Restricted Cash and Cash Equivalents, Current	$ 2,200,000			$ 2,200,000		2,200,000
Disposal Group Including Discontinued Operation, Working Capital Adjustment						$ 220,000