Note 3 - Accumulated Other Comprehensive Income (Details) - Changes in Accumulated Other Comprehensive Income by Component - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 5,466	$ 497	$ 4,875	$ (3,212)
Other comprehensive (loss) income before reclassifications	(3,035)	4,973	(2,389)	8,577
Amounts reclassified from accumulated other comprehensive income	(16)	8	(71)	113
Net current-period other comprehensive (loss) income	(3,051)	4,981	(2,460)	8,690
Ending balance	2,415	5,478	2,415	5,478
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	7,001	63	5,174	(3,623)
Other comprehensive (loss) income before reclassifications	(3,035)	4,973	(1,138)	8,577
Amounts reclassified from accumulated other comprehensive income	(31)	(15)	(101)	67
Net current-period other comprehensive (loss) income	(3,066)	4,958	(1,239)	8,644
Ending balance	3,935	5,021	3,935	5,021
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(1,535)	434	(299)	411
Other comprehensive (loss) income before reclassifications			(1,251)
Amounts reclassified from accumulated other comprehensive income	15	23	30	46
Net current-period other comprehensive (loss) income	15	23	(1,221)	46
Ending balance	$ (1,520)	$ 457	$ (1,520)	$ 457