Note 6 - Fair Value Measurements - Change in Fair Value Measurement Impacts Net Income (Details) - Valuation, Market Approach [Member] - Current Reference Price [Member]	Sep. 30, 2021	Dec. 31, 2020
Interest Rate Contract [Member] | Minimum [Member]
Derivative asset (liability)	1.0037	1.0191
Interest Rate Contract [Member] | Maximum [Member]
Derivative asset (liability)	1.0113	1.0302
Forward Contract [Member] | Minimum [Member]
Derivative asset (liability)	1.0037	1.0191
Forward Contract [Member] | Maximum [Member]
Derivative asset (liability)	1.0267	1.0319