Note 4 - Non-operating Income - Schedule of Non-operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Equity in earnings of unconsolidated investments	$ 1,854	$ 1,615	$ 3,380	$ 3,120
Dividends and other net realized gains and losses on sales of securities	1,899	1,901	3,623	3,762
Interest income	1,436	1,409	2,954	2,816
Other non-operating income	$ 5,189	$ 4,925	$ 9,957	$ 9,698