Note 2 - Accumulated Other Comprehensive Income (Details) - Changes in Accumulated Other Comprehensive Income by Component (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (3,212)	$ 6,869
Other comprehensive income (loss) before reclassifications	7,933	(10,214)
Amounts reclassified from accumulated other comprehensive income	154	133
Net current-period other comprehensive income (loss)	8,087	(10,081)
Ending balance	4,875	(3,212)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(3,623)	9,411
Other comprehensive income (loss) before reclassifications	8,734	(12,992)
Amounts reclassified from accumulated other comprehensive income	63	(42)
Net current-period other comprehensive income (loss)	8,797	(13,034)
Ending balance	5,174	(3,623)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	411	(2,542)
Other comprehensive income (loss) before reclassifications	(801)	2,778
Amounts reclassified from accumulated other comprehensive income	91	175
Net current-period other comprehensive income (loss)	(710)	2,953
Ending balance	$ (299)	$ 411