Note 8 - Leases - Lease Expense (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Amortization of right-of-use assets	$ 27,645,000
Interest on lease liabilities	1,720,000
Operating lease cost	181,718,000	184,710,000
Sublease income	(10,300,000)
Total lease costs	200,783,000	$ 184,710,000
Operating cash flows from financing leases
Operating cash flows from operating leases	16,798
Financing cash flows from financing leases
Weighted-average remaining lease term - financing leases (in years) (Year)	4 years 36 days
Weighted-average remaining lease term - operating leases (in years) (Year)	15 years 255 days
Weighted-average discount rate - financing leases	2.05%
Weighted-average discount rate - operating leases	5.50%