Note 6 - Leases - Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Amortization of right-of-use assets	$ 44,657	$ 30,977
Interest on lease liabilities	1,696	2,096
Operating lease cost	272,545	272,335
Sublease income	(6,300)	(12,300)
Total lease costs	$ 312,598	$ 293,108
Weighted-average remaining lease term - financing leases (in years) (Year)	3 years 4 months 24 days	3 years 3 months 18 days
Weighted-average remaining lease term - operating leases (in years) (Year)	14 years 2 months 12 days	14 years 10 months 24 days
Weighted-average discount rate - financing leases	1.20%	1.96%
Weighted-average discount rate - operating leases	5.70%	5.62%