Segment Reporting (Details 1) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Segment Reporting [Abstract]
Assets, Net	[1]	$ 1,207,851	$ 1,215,783	$ 1,520,442
Cash and cash equivalents		77,148	55,645	$ 65,319
Other assets		86,147	107,208
TOTAL ASSETS		$ 1,371,146	$ 1,378,636

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