Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Finite-Lived Intangible Assets

The gross and net balances are set forth in the following table:

	Gross Carrying Amount		Accumulated Amortization		Net Balance
Balance at December 31, 2020
Coal supply agreement	$	84,200	$	(48,870)	$	35,330
Balance at December 31, 2019
Coal supply agreement	$	84,200	$	(46,298)	$	37,902