Note 5 - Accumulated Other Comprehensive Income (Details) - Changes in Accumulated Other Comprehensive Income (USD $) In Thousands, unless otherwise specified						3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013	Sep. 30, 2013		Sep. 30, 2014 Accumulated Net Unrealized Investment Gain (Loss) [Member] Metropolitan District Bond Securities [Member]		Sep. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member] Metropolitan District Bond Securities [Member]		Sep. 30, 2014 Accumulated Net Unrealized Investment Gain (Loss) [Member] Metropolitan District Bond Securities [Member]		Sep. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member] Metropolitan District Bond Securities [Member]		Sep. 30, 2014 Accumulated Net Unrealized Investment Gain (Loss) [Member]		Sep. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member]		Sep. 30, 2014 Accumulated Net Unrealized Investment Gain (Loss) [Member]		Sep. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member]
Unrealized gains (losses) on available-for-sale marketable securities 1 :
Beginning balance	$ 7,372	[1]	$ 11,575	$ 7,338	[1]	$ 4,510	[1]	$ 4,494	[1]	$ 3,920	[1]		[1]	$ 5,346	[1]	$ 884	[1]	$ 7,655	[1]	$ 4,838	[1]
Other comprehensive income before reclassifications						490	[1]		[1]	1,080	[1]	4,494	[1]	(4,836)	[1]	1,766	[1]	(3,236)	[1]	(1,195)	[1]
Amounts reclassified from accumulated other comprehensive income						0	[1]	0	[1]	0	[1]	0	[1]	1,862	[1],[2]	194	[1],[2]	(2,047)	[1],[2]	(799)	[1],[2]
Ending balance	7,372	[1]	11,575	7,338	[1]	5,000	[1]	4,494	[1]	5,000	[1]	4,494	[1]	2,372	[1]	2,844	[1]	2,372	[1]	2,844	[1]
Total ending AOCI	$ 7,372	[1]	$ 11,575	$ 7,338	[1]	$ 5,000	[1]	$ 4,494	[1]	$ 5,000	[1]	$ 4,494	[1]	$ 2,372	[1]	$ 2,844	[1]	$ 2,372	[1]	$ 2,844	[1]

[1] All amounts net-of-tax.

[2] See separate table below for details about these reclassifications which include gains or losses on sales of available-for-sale securities sold as well as anyother-than-temporary impairments taken on available-for-sale securities during the period.