Note 10 - Product Warranty Obligations - Recognition of Deferred Revenue Related to Extended Warranties 2 (Details) $ in Thousands	Sep. 30, 2019 USD ($)
Revenue performance obligation, expected timing	$ 76,862
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue performance obligation, expected timing	3,704
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue performance obligation, expected timing	15,250
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue performance obligation, expected timing	15,678
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue performance obligation, expected timing	13,831
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue performance obligation, expected timing	10,535
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue performance obligation, expected timing	$ 17,864