Note 14 - Employee Benefit Plan (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Partnership's Employee Unit Purchase Plan [Member]
Employee Stock Ownership Plan (ESOP), Shares in ESOP, Total	1,000,000
Employee Stock Ownership Plan (ESOP), Compensation Expense	$ 0.1	$ 0.1
Partnership's 401(k) Plan [Member]
Defined Contribution Plan, Employer Discretionary Contribution Amount	1.1	1.2
Defined Contribution Plan, Employer Discretionary Profit Sharing Contribution Amount	$ 0.7	$ 0.2