Note 10 - Property, Plant and Equipment (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finance Lease, Right-of-Use Asset, before Accumulated Amortization	$ 112,334	$ 52,729
Finance Lease, Right-of-Use Asset, Accumulated Amortization	56,761	31,373
Finance Lease, Right-of-Use Asset, Amortization	$ 24,066	$ 15,691	$ 13,148