Note 15 - Leases (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Operating Lease, Right-of-Use Asset	$ 72,244	$ 73,439	$ 72,244	$ 73,439	$ 72,534
Operating Lease, Liability, Noncurrent	56,071	60,868	56,071	60,868	$ 58,618
Operating Lease, Expense	$ 5,400	$ 4,600	$ 10,600	$ 8,900
Operating Lease, Weighted Average Remaining Lease Term (Year)	5 years 4 months 24 days	6 years 3 months 18 days	5 years 4 months 24 days	6 years 3 months 18 days	5 years 9 months 18 days
Operating Lease, Weighted Average Discount Rate, Percent	3.90%	4.08%	3.90%	4.08%	3.97%
ROU Assets [Member]
Operating Lease, Right-of-Use Asset	$ 19,000	$ 19,000	$ 19,000	$ 19,000	$ 19,000
Other Current Liabilities [Member]
Operating Lease, Liability, Current	17,000	17,000	17,000	17,000	17,000
Long-term Lease Liabilities [Member]
Operating Lease, Liability, Noncurrent	$ 15,600	$ 15,600	$ 15,600	$ 15,600	$ 15,600
Maximum [Member]
Lessee, Operating Lease, Term of Contract (Year)	23 years		23 years