Note 6 - Fair Value Measurements (Details) - Summary of Activity for Metro Bonds (Metropolitan District Bond Securities [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Metropolitan District Bond Securities [Member]
Note 6 - Fair Value Measurements (Details) - Summary of Activity for Metro Bonds [Line Items]
Balance at beginning of period	$ 12,729	$ 5,818
Increase in fair value (recorded in other comprehensive income)	6,114	6,373
Change due to accretion of principal	1,405	1,192
Cash receipts	(2,045)	(654)
Balance at end of period	$ 18,203	$ 12,729