Note 8 - Leases - Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Amortization of right-of-use assets	$ 142,582	$ 111,559
Interest on lease liabilities	7,736	8,346
Operating lease cost	1,081,620	1,080,226
Sublease income	(47,200)	(45,200)
Total lease costs	$ 1,184,738	$ 1,154,931
Weighted-average remaining lease term - financing leases (in years) (Year)	3 years 4 months 24 days	3 years 6 months
Weighted-average remaining lease term - operating leases (in years) (Year)	14 years 4 months 24 days	15 years 2 months 12 days
Weighted-average discount rate - financing leases	1.32%	1.96%
Weighted-average discount rate - operating leases	5.68%	5.60%