Segment Reporting (Details 1) - USD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting [Abstract]
Assets, Net	[1]	$ 1,232,153	$ 1,215,783	$ 1,550,671
Cash and cash equivalents		92,794	55,645
Other assets		79,030	107,208
TOTAL ASSETS		$ 1,403,977	$ 1,378,636

[1] Segment assets include receivables, prepaids, inventories, property, plant and equipment, and mineral interests