Note 5 - Accumulated Other Comprehensive Income (Details) - Changes in Accumulated Other Comprehensive Income (USD $) In Thousands, unless otherwise specified						3 Months Ended				6 Months Ended				3 Months Ended				6 Months Ended
	Jun. 30, 2014		Dec. 31, 2013	Jun. 30, 2013		Jun. 30, 2014 Accumulated Net Unrealized Investment Gain (Loss) [Member] Metropolitan District Bond Securities [Member]		Jun. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member] Metropolitan District Bond Securities [Member]		Jun. 30, 2014 Accumulated Net Unrealized Investment Gain (Loss) [Member] Metropolitan District Bond Securities [Member]		Jun. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member] Metropolitan District Bond Securities [Member]		Jun. 30, 2014 Accumulated Net Unrealized Investment Gain (Loss) [Member]		Jun. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member]		Jun. 30, 2014 Accumulated Net Unrealized Investment Gain (Loss) [Member]		Jun. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member]
Unrealized gains (losses) on available-for-sale marketable securities 1 :
Beginning balance	$ 9,856	[1]	$ 11,575	$ 5,378	[1]	$ 3,920	[1]		[1]	$ 3,920	[1]		[1]	$ 3,609	[1]	$ 7,373	[1]	$ 7,655	[1]	$ 4,838	[1]
Other comprehensive income before reclassifications						590	[1]	4,494	[1]	590	[1]	4,494	[1]	1,633	[1]	(5,274)	[1]	1,600	[1]	(3,053)	[1]
Amounts reclassified from accumulated other comprehensive income						0	[1]	0	[1]	0	[1]	0	[1]	104	[1],[2]	(1,215)	[1],[2]	(3,909)	[1],[2]	(901)	[1],[2]
Ending balance	9,856	[1]	11,575	5,378	[1]	4,510	[1]	4,494	[1]	4,510	[1]	4,494	[1]	5,346		884		5,346		884
Total ending accumulated other comprehensive income	$ 9,856	[1]	$ 11,575	$ 5,378	[1]	$ 4,510	[1]	$ 4,494	[1]	$ 4,510	[1]	$ 4,494	[1]	$ 5,346		$ 884		$ 5,346		$ 884

[1] All amounts net-of-tax.

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