Segment Reporting (Details 1) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting [Abstract]
Assets, Net	[1]	$ 1,215,783	$ 1,550,671	$ 1,550,671	$ 1,344,553
Cash and cash equivalents		55,645	115,081
Other assets		107,208	46,748
TOTAL ASSETS		$ 1,378,636	$ 1,712,500

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