Commitments and Contingencies (Tables)

6 Months Ended

Jun. 30, 2020

Commitments and Contingencies Disclosure [Abstract]

Schedule of Restricted Cash Deposits

Amounts included in restricted cash represent cash deposits primarily invested in interest bearing accounts that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral for securing the following obligations which have been written on the Company’s behalf:

	June 30, 2020		December 31, 2019
Workers' compensation	$	39,135	$	38,944
Black lung	12,768		12,706
Reclamation-related obligations	55,019		67,868
Financial guarantees and other	3,008		3,006
Contingent revenue obligation escrow	3,720		12,363
Total restricted cash	113,650		134,887
Less current portion (1)	(3,720)		(12,363)
Restricted cash, net of current portion	$	109,930	$	122,524

⁽¹⁾ Included within prepaid expenses and other current assets on the Company’s Condensed Consolidated Balance Sheets.

Schedule of Restricted Investments and Deposit Assets

Amounts included in restricted investments consist of certificates of deposit, mutual funds, and U.S. treasury bills that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral for securing the following obligations which have been written on the Company’s behalf:

	June 30, 2020		December 31, 2019
Workers' compensation	$	3,131	$	3,100
Reclamation-related obligations	26,715		18,786
Total restricted investments (1), (2)	$	29,846	$	21,886

⁽¹⁾ Included within other non-current assets on the Company’s Condensed Consolidated Balance Sheets.

⁽²⁾ As of June 30, 2020 and December 31, 2019, respectively, $27,413 and $13,508 are classified as trading securities and $2,433 and $8,378 are classified as held-to-maturity securities.

Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral to secure the following obligations which have been written on the Company’s behalf:

	June 30, 2020		December 31, 2019
Reclamation-related obligations	$	14,143	$	8,887
Other operating agreements	1,459		1,836
Total deposits (1)	$	15,602	$	10,723

⁽¹⁾ Included within prepaid expenses and other current assets and other non-current assets on the Company’s Condensed Consolidated Balance Sheets.