Note 11 - Reclassifications from Accumulated Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Beginning balance			$ 332,813
Ending balance	$ 345,715		345,715
AOCI Attributable to Parent [Member]
Beginning balance	7,499	$ 3,372	3,540	$ 2,055
Other comprehensive income before reclassifications	670	672	4,259	1,727
Amounts reclassified from accumulated other comprehensive income	(17)	210	353	472
Net current-period other comprehensive income	653	882	4,612	2,199
Ending balance	$ 8,152	$ 4,254	$ 8,152	$ 4,254

Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 55
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=84158357&loc=d3e1436-108581

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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