Note 6 - Debt, Credit Facilitiy and Leases - Credit Facility (Details) - New Facility [Member]	12 Months Ended
	Dec. 31, 2019
Minimum [Member]
Standby fee per annum on undrawn amounts	0.5625%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Variable rate	2.25%
Minimum [Member] | Base Rate [Member]
Variable rate	1.25%
Maximum [Member]
Standby fee per annum on undrawn amounts	1.00%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Variable rate	4.00%
Maximum [Member] | Base Rate [Member]
Variable rate	3.00%