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		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income tax expense	$ (1,959)	$ (1,127)	$ (3,079)	$ (2,445)
Net of tax	4,261	3,060	7,094	6,367
	6,783	4,674	11,273	9,784
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Unrealized gains and losses on available for sale investment securities	23	62	(103)	51
Income tax expense	(8)	(22)	36	(18)
Net of tax	15	40	(67)	33
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income tax expense	13	23	25	46
Net of tax	(23)	(44)	(46)	(88)
Prior service costs	(52)	(64)	(104)	(128)
Actuarial gains (losses)	16	(3)	33	(6)
	(36)	(67)	(71)	(134)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net of tax	$ (8)	$ (4)	$ (113)	$ (55)