Segment Reporting (Details 1) - USD ($) $ in Thousands		Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Segment Reporting [Abstract]
Assets, Net	[1]	$ 1,208,875	$ 1,215,783	$ 1,535,465
Cash and cash equivalents		70,924	55,645	$ 37,907
Other assets		81,281	107,208
TOTAL ASSETS		$ 1,361,080	$ 1,378,636

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