Note 4 - Fair Value Measurements and Derivative Financial Instruments - Effect of Cash Flow Hedge Accounting on the Company's Statement of Operations (Details) - Interest Expense [Member] - Designated as Hedging Instrument [Member] - Cash Flow Hedging [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Hedged interest payments	$ (1,570)	$ (2,327)	$ (5,328)	$ (5,524)
(Loss) gain on interest rate swap	$ (507)	$ 197	$ (898)	$ 648