Note 3 - Accumulated Other Comprehensive Income (Details) - Changes in Accumulated Other Comprehensive Income by Component - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 2,415	$ 5,478	$ 4,875	$ (3,212)
Other comprehensive income (loss) before reclassifications	1,905	(1,522)	(504)	7,049
Amounts reclassified from accumulated other comprehensive income	10	15	(41)	134
Net current-period other comprehensive income (loss)	1,915	(1,507)	(545)	7,183
Ending balance	4,330	3,971	4,330	3,971
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	3,935	5,021	5,174	(3,623)
Other comprehensive income (loss) before reclassifications	1,905	(1,522)	747	7,049
Amounts reclassified from accumulated other comprehensive income	(5)	(7)	(86)	66
Net current-period other comprehensive income (loss)	1,900	(1,529)	661	7,115
Ending balance	5,835	3,492	5,835	3,492
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(1,520)	457	(299)	411
Other comprehensive income (loss) before reclassifications	0	0	(1,251)	0
Amounts reclassified from accumulated other comprehensive income	15	22	45	68
Net current-period other comprehensive income (loss)	15	22	(1,206)	68
Ending balance	$ (1,505)	$ 479	$ (1,505)	$ 479