Note 8 - Leases - Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating lease right of use asset	$ 31,624
Operating lease accumulated depreciation	(5,825)
Operating lease right of use asset, net	25,799	$ 30,100
Operating lease current liabilities	5,481
Operating lease liabilities	20,418
	25,899	$ 30,100
Property and equipment, at cost	416,511		$ 403,785
Accumulated depreciation	(260,264)		$ (244,176)
Finance lease right of use asset, net	546
Finance lease current liabilities	108
Finance lease liabilities	443
	$ 551
Operating leases (Year)	7 years
Finance leases (Year)	6 years
Operating leases	3.72%
Finance leases	4.01%
Assets Held Under Finance Leases [Member]
Property and equipment, at cost	$ 613
Accumulated depreciation	$ (67)