Note 10 - Leases - Operating Lease Related Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Right-of-use assets - operating leases	$ 34,217	$ 33,990
Lease liabilities - operating leases	$ 36,408	$ 35,873
Weighted-average remaining lease term (in years) (Year)	5 years	5 years 4 months 24 days
Weighted-average discount rate	2.85%	3.10%