Note 3 - Revenues From Contracts With Customers; Other Revenues (Details Textual) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Revenue from Contract with Customer, Including Assessed Tax	$ 3,825	$ 6,403
Contract with Customer, Asset, after Allowance for Credit Loss, Total	0		$ 0
Contract with Customer, Asset, Credit Loss Expense (Reversal)	0		0
Transferred at Point in Time [Member]
Revenue from Contract with Customer, Including Assessed Tax	3,825	6,403
Transferred at Point in Time [Member] | Variable Consideration or Multiple Performance Obligations [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	0
Revenue, Remaining Performance Obligation, Amount	0		0
Transferred over Time [Member]
Revenue from Contract with Customer, Including Assessed Tax
Transferred over Time [Member] | Variable Consideration or Multiple Performance Obligations [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	$ 0
Revenue, Remaining Performance Obligation, Amount	$ 0		$ 0