Note 13 - Property and Equipment, Net - Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	[1]	Sep. 30, 2021
Property and equipment, gross	$ 1,497,022	$ 1,342,395		$ 1,513,794
Less: accumulated depreciation and depletion	996,195	908,891		1,003,136
Property and equipment, net	500,827	433,504		510,658
Equipment and Vehicles [Member]
Property and equipment, gross	989,754	870,672		997,560
Mining Properties and Mineral Rights [Member]
Property and equipment, gross	205,369	191,982		188,838
Land and Land Improvements [Member]
Property and equipment, gross	115,308	108,518		126,130
Building and Building Improvements [Member]
Property and equipment, gross	104,108	96,180		123,207
Furniture and Fixtures [Member]
Property and equipment, gross	$ 82,483	$ 75,043		$ 78,059

[1] These balances do not include amounts held for sale (see Note 3).