Note 6 - Other Comprehensive Income (Loss) - Accumulated Other Comprehensive Income (Loss) by Component (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated other comprehensive income (loss)			$ 965	$ 2,456
Net current period other comprehensive loss			5,256	(751)
Accumulated other comprehensive income (loss)	$ 6,221	$ 1,705	6,221	1,705
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated other comprehensive income (loss)			(60)	16
Net current period other comprehensive loss			(438)	(21)
Accumulated other comprehensive income (loss)	(498)	(5)	(498)	(5)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated other comprehensive income (loss)			(273)	(387)
Net current period other comprehensive loss
Accumulated other comprehensive income (loss)	(273)	(387)	(273)	(387)
Accumulated other comprehensive income (loss)			632	2,085
Net current period other comprehensive loss	1,504	(2,633)	4,818	(772)
Accumulated other comprehensive income (loss)	$ 5,450	$ 1,313	$ 5,450	$ 1,313

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e637-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e681-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=66004124&loc=SL7669686-108580

Name:	us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant