Note 3 - Revenue from Contracts with Customers 2 (Details Textual)
Feb. 29, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-03-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year) 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-03-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year) 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-03-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year) 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-03-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year) 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-03-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year) 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-03-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year) 1 year
Minimum [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year) 10 years
Maximum [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Year) 0 years