Note 12 - Fair Value of Financial Instruments - Summary of Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Reported Value Measurement [Member]
Cash and Cash Equivalents	$ 921	$ 861
Short-Term Debt	(108,997)	(18,599)
Long-Term Debt including Current Maturities	(590,195)	(590,174)
Estimate of Fair Value Measurement [Member]
Cash and Cash Equivalents	921	861
Short-Term Debt	(108,997)	(18,599)
Long-Term Debt including Current Maturities	$ (663,761)	$ (601,513)