Note 6 - Interest Rate Swap Derivatives - Fair Values of Derivative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2017	Dec. 31, 2016
Notional amount	$ 250,000	$ 250,000
Fair value	463	(692)
Interest Rate Swap 1 [Member] \| Other Liabilities [Member]
Notional amount	75,000	75,000
Fair value	$ 100	$ (197)
Pay rate	1.71%	1.71%
Maturity	Mar. 31, 2020	Mar. 31, 2020
Interest Rate Swap 2 [Member] \| Other Liabilities [Member]
Notional amount	$ 100,000	$ 100,000
Fair value	$ 35	$ (514)
Pay rate	1.74%	1.74%
Maturity	Apr. 15, 2021	Apr. 15, 2021
Interest Rate Swap 3 [Member] \| Other Liabilities [Member]
Notional amount	$ 75,000	$ 75,000
Fair value	$ 328	$ 19
Pay rate	1.92%	1.92%
Maturity	Mar. 31, 2022	Mar. 31, 2022

Fair value of the assets less the liabilities of a derivative or group of derivatives.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant