Note 2 - Investments and Restricted Cash (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Sep. 30, 2016	Dec. 31, 2015
Available-for-sale Securities, Debt Securities, Current			$ 24,500,000	$ 0
Available-for-sale Securities, Equity Securities, Noncurrent			6,400,000	1,500,000
Available-for-sale Equity Securities, Amortized Cost Basis			4,100,000	4,000,000
Available-for-sale Equity Securities, Acquired During Period, Cost Basis			900,000
Other than Temporary Impairment Losses, Investments	$ 1,000,000	$ 2,800,000
Restricted Cash and Investments, Current			3,900,000
Restricted Investments			$ 2,200,000	$ 1,000,000