Note 10 - Long-term Incentive Plan - Activity Pertaining to Phantom and Restricted Common Stock Unit Awards (Details) - Long-Term Incentive Plan [Member] - Phantom and Restricted Units Holders [Member]	3 Months Ended
	Mar. 31, 2022 $ / shares shares
Nonvested, number of units, beginning balance (in shares) | shares	1,555,290
Nonvested, weighted average grant date fair value, beginning balance (in dollars per share) | $ / shares	$ 1.66
Granted, number of units (in shares) | shares	558,411
Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 3.25
Vested, number of units (in shares) | shares	426,297
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 1.14
Nonvested, number of units, ending balance (in shares) | shares	1,687,404
Nonvested, weighted average grant date fair value, ending balance (in dollars per share) | $ / shares	$ 2.30