Note 13 - Derivative Financial Instruments - Summary of Fair Value Amounts of Derivative Instruments (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Derivative assets	$ 785,000	$ 3,648,000
Derivative liabilities	4,912,000	1,929,000
Net derivative assets (liabilities)	(4,127,000)	1,719,000
Designated as Hedging Instrument [Member]
Derivative assets	785,000	3,648,000
Derivative liabilities	4,871,000	1,885,000
Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member]
Derivative assets	785,000	3,648,000
Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member]
Derivative liabilities	4,871,000	1,885,000
Not Designated as Hedging Instrument [Member]
Derivative assets	0	0
Derivative liabilities	41,000	44,000
Not Designated as Hedging Instrument [Member] | Prepaid Expenses and Other Current Assets [Member]
Derivative assets	0	0
Not Designated as Hedging Instrument [Member] | Accrued Expense [Member]
Derivative liabilities	$ 41,000	$ 44,000