Note 4 - Fair Value Measurements and Derivative Financial Instruments - Summary of Financial Instruments Designated as Cash Flow Hedges (Details) - Designated as Hedging Instrument [Member] - Interest Rate Swap [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Other Assets [Member]
Notional Amount	$ 90,000
Fair Value	$ 218
Other Noncurrent Liabilities [Member]
Notional Amount		$ 90,000
Fair Value		$ 458