Note 7 - Long-term Leases - Maturity of Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
2020, finance leases	$ 5,200
2020, operating leases	35,674
2021, finance leases	5,200
2021, operating leases	35,326
2022, finance leases	5,200
2022, operating leases	35,015
2023, finance leases	5,200
2023, operating leases	34,489
2024, finance leases	2,167
2024, operating leases	34,345
Thereafter, finance leases	0
Thereafter, operating leases	82,711
Total minimum lease payments, finance leases	22,967
Total minimum lease payments, operating leases	257,560
Less: amounts representing interest, finance leases	(2,835)
Less: amounts representing interest, operating leases	(48,775)
Present value of future minimum lease payments, finance leases	20,132
Present value of future minimum lease payments, operating leases	208,785
Less: current portion, finance leases	(4,104)	$ (3,924)
Less: current portion, operating leases	(23,988)	0
Noncurrent lease liabilities, finance leases	16,028	19,128
Noncurrent lease liabilities, operating leases	$ 184,797	$ 0