Note 3 - Accumulated Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Beginning balance	$ 7,516,000	$ 3,935,000	$ 3,219,000	$ 5,174,000
Other comprehensive (loss) income before reclassifications	(1,531,000)	1,899,000	2,905,000	767,000
Amounts reclassified from accumulated other comprehensive income	(2,454,000)	1,000	(2,593,000)	(106,000)
Net current-period other comprehensive (loss) income	(3,985,000)	1,900,000	312,000	661,000
Ending balance	3,531,000	5,835,000	3,531,000	5,835,000
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Beginning balance	(419,000)	(1,520,000)	(437,000)	(299,000)
Other comprehensive (loss) income before reclassifications	0	0	0	(1,251,000)
Amounts reclassified from accumulated other comprehensive income	9,000	15,000	27,000	45,000
Net current-period other comprehensive (loss) income	9,000	15,000	27,000	(1,206,000)
Ending balance	(410,000)	(1,505,000)	(410,000)	(1,505,000)
Beginning balance	7,097,000	2,415,000	2,782,000	4,875,000
Other comprehensive (loss) income before reclassifications	(1,531,000)	1,899,000	2,905,000	(484,000)
Amounts reclassified from accumulated other comprehensive income	(2,445,000)	16,000	(2,566,000)	(61,000)
Net current-period other comprehensive (loss) income	(3,976,000)	1,915,000	339,000	(545,000)
Ending balance	$ 3,121,000	$ 4,330,000	$ 3,121,000	$ 4,330,000