Note 13 - Stockholders' Equity - Components of Accumulated Other Comprehensive Loss and Changes During the Year (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Beginning balance, net of tax	$ (5,562)	$ (2,907)	$ (11,375)
Other comprehensive income (loss) before reclassifications, net of tax	(2,217)	(3,203)	9,758
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(583)	548	(1,290)
Total other comprehensive income (loss), net of tax	(2,800)	(2,655)	8,468
Ending balance, net of tax	(8,362)	(5,562)	(2,907)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Beginning balance, net of tax	(521)	3,392	(8,522)
Other comprehensive income (loss) before reclassifications, net of tax	(2,452)	(3,818)	13,548
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(886)	(95)	(1,634)
Total other comprehensive income (loss), net of tax	(3,338)	(3,913)	11,914
Ending balance, net of tax	(3,859)	(521)	3,392
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Beginning balance, net of tax	(5,041)	(6,299)	(2,853)
Other comprehensive income (loss) before reclassifications, net of tax	235	615	(3,790)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	303	643	344
Total other comprehensive income (loss), net of tax	538	1,258	(3,446)
Ending balance, net of tax	$ (4,503)	$ (5,041)	$ (6,299)