Note 4 - Fair Value Measurement (Details) - Level 3 Investments - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at January 1, 2014	$ 5,389
Ending balance	5,361	$ 5,389
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at January 1, 2014	5,389	9,860
Sales and settlement at par		(4,650)
Change in unrealized loss included in other comprehensive income	(28)	179
Ending balance	$ 5,361	$ 5,389