Note 4 - Other Long-term Assets - Other Long-term Assets (Details) - USD ($) $ in Thousands		Jun. 30, 2020	Dec. 31, 2019
Advanced coal royalties		$ 6,303	$ 6,105
Marketable equity securities available for sale, at fair value (restricted)*	[1]	0	2,296
Other		1,866	1,923
Total other assets		$ 8,169	$ 10,324

[1] Held by Sunrise Indemnity, Inc., our wholly-owned captive insurance company.