Provision for Site Reclamation and Closure (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure Of Provision For Site Reclamation And Closure [Abstract]

Summary of Detailed Information about Provision for Site Reclamation and Closure

Balance at January 1, 2018	$	4,101
Addition of Florida Canyon Mine at the Closing Date		30,227
Accretion of discounted cash flows		876
Change in estimated cash flows and assumptions		2,426
Balance at December 31, 2018	$	37,630
Accretion of discounted cash flows		1,250
Change in estimated cash flows and assumptions		(3,240	)
Balance at December 31, 2019	$	35,640