Note 7 - Long-term Leases - Maturity of Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
2020, finance leases	$ 5,200
2020, operating leases	35,495
2021, finance leases	5,200
2021, operating leases	35,169
2022, finance leases	5,200
2022, operating leases	34,748
2023, finance leases	4,766
2023, operating leases	34,430
2024, finance leases	0
2024, operating leases	34,279
Thereafter, finance leases	0
Thereafter, operating leases	65,600
Total minimum lease payments, finance leases	20,366
Total minimum lease payments, operating leases	239,721
Less: amounts representing interest, finance leases	(2,256)
Less: amounts representing interest, operating leases	(42,761)
Present value of future minimum lease payments, finance leases	18,110
Present value of future minimum lease payments, operating leases	196,960
Less: current portion, finance leases	(4,228)	$ (4,166)
Less: current portion, operating leases	(24,557)	(24,243)
Noncurrent lease liabilities, finance leases	13,882	14,963
Noncurrent lease liabilities, operating leases	$ 172,403	$ 178,666