Note 3 - Accumulated Other Comprehensive Income (Details) - Amounts Reclassified out of Accumulated Other Comprehensive Income by Component (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	$ (1,283)	$ (855)	$ (4,362)	$ (3,300)
Net of tax	3,657	2,546	10,751	8,913
	5,390	3,890	16,663	13,674
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains and losses on available for sale investment securities	11	2	(102)	58
Income tax expense	(4)	(1)	36	(20)
Net of tax	7	1	(66)	38
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	12	25	37	71
Net of tax	(22)	(43)	(68)	(131)
Prior service costs	(51)	(65)	(155)	(193)
Actuarial gains (losses)	17	(3)	50	(9)
	(34)	(68)	(105)	(202)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	$ (15)	$ (42)	$ (134)	$ (93)