Note 9 - Financial Instruments and Fair Value - Fair Values of Derivative Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest rate swaps	$ 14,900	$ 13,963	$ 11,437
Interest rate swaps	(14,900)	(13,963)	$ (11,437)
Other Noncurrent Liabilities [Member]
Interest rate swaps		235
Interest rate swaps		55
Interest rate swaps		$ (55)

Amount of the cost of borrowed funds accounted for as interest expense.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.9)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration