Note 15 - Leases (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Operating Lease, Right-of-Use Asset	$ 72,945	$ 71,480	$ 72,534
Operating Lease, Liability, Noncurrent	57,985	60,237	$ 58,618
Operating Lease, Expense	$ 5,200	$ 4,300
Operating Lease, Weighted Average Remaining Lease Term (Year)	5 years 7 months 6 days	6 years 7 months 6 days	5 years 9 months 18 days
Operating Lease, Weighted Average Discount Rate, Percent	3.94%	4.13%	3.97%
ROU Assets [Member]
Operating Lease, Right-of-Use Asset	$ 17,900	$ 17,900	$ 17,900
Other Current Liabilities [Member]
Operating Lease, Liability, Current	17,000	17,000	17,000
Long-term Lease Liabilities [Member]
Operating Lease, Liability, Noncurrent	$ 14,300	$ 14,300	$ 14,300
Maximum [Member]
Lessee, Operating Lease, Term of Contract (Year)	23 years