Note 10 - Product Warranty Obligations - Recognition of Deferred Revenue Related to Extended Warranties 2 (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Revenue performance obligation	$ 80,880
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Revenue performance obligation	12,192
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue performance obligation	17,253
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue performance obligation	15,782
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue performance obligation	12,351
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue performance obligation	8,173
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue performance obligation	$ 15,129