Note 8 - Leases - Lease Expense (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Amortization of right-of-use assets	$ 54,858,000		$ 27,213,000
Interest on lease liabilities	3,872,000		2,152,000
Operating lease cost	540,082,000	397,100,000	270,040,000	212,390,000
Sublease income	(22,600,000)		(12,300,000)
Total lease costs	$ 576,212,000	$ 397,100,000	287,105,000	$ 212,390,000
Operating cash flows from financing leases
Operating cash flows from operating leases			30,078
Financing cash flows from financing leases
Weighted-average remaining lease term - financing leases (in years) (Year)	3 years 328 days		3 years 328 days
Weighted-average remaining lease term - operating leases (in years) (Year)	15 years 182 days		15 years 182 days
Weighted-average discount rate - financing leases	2.05%		2.05%
Weighted-average discount rate - operating leases	5.50%		5.50%