Note 5 - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] | Metropolitan District Bond Securities [Member]
Beginning balance	[1]	$ 12,647	$ 8,621	$ 12,058	$ 7,680
Other comprehensive income (loss) before reclassifications	[1]	567	1,193	1,156	2,134
Amounts reclassified from AOCI	[1]
Ending balance	[1]	13,214	9,814	13,214	9,814
Ending balance	[1]	12,647	8,621	12,058	7,680
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Beginning balance	[1]	5,016	3,142	3,657	2,775
Other comprehensive income (loss) before reclassifications	[1]	880	(1,260)	1,404	(900)
Amounts reclassified from AOCI	[1],[2]	(552)	(293)	283	(286)
Ending balance	[1]	5,344	1,589	5,344	1,589
Ending balance	[1]	5,016	3,142	3,657	2,775
Beginning balance				15,715
Ending balance	[1]	18,558	11,403	18,558	11,403
Ending balance	[1]	$ 18,558	$ 11,403	$ 18,558	$ 11,403

[1] All amounts net-of-tax.

[2] See separate table below for details about these reclassifications