Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 135,590	$ 135,520
Accounts receivable, net	32,729	24,538
Other current assets, net	3,510	2,723
Total current assets	171,829	162,781
Land	24,008	24,008
Mineral rights, net	433,965	437,697
Intangible assets, net	16,019	16,130
Equity in unconsolidated investment	280,156	276,004
Long-term contract receivable, net	30,783	31,371
Other long-term assets, net	5,528	5,832
Total assets	962,288	953,823
Current liabilities
Accounts payable	1,896	1,956
Accrued liabilities	3,388	10,297
Accrued interest	8,463	1,213
Current portion of deferred revenue	15,420	11,817
Current portion of long-term debt, net	39,046	39,102
Total current liabilities	68,213	64,385
Deferred revenue	39,126	50,045
Long-term debt, net	378,163	394,443
Other non-current liabilities	4,803	5,018
Total liabilities	490,305	513,891
Commitments and contingencies (see Note 12)
Class A Convertible Preferred Units (250,000 and 269,321 units issued and outstanding at March 31, 2022 and December 31, 2021, respectively, at $1,000 par value per unit; liquidation preference of $1,850 per unit at March 31, 2022 and December 31, 2021)	164,587	183,908
Partners’ capital
Common unitholders’ interest (12,505,996 and 12,351,306 units issued and outstanding at March 31, 2022 and December 31, 2021, respectively)	250,767	203,062
General partner’s interest	2,909	1,787
Warrant holders’ interest	47,964	47,964
Accumulated other comprehensive income	5,756	3,211
Total partners’ capital	307,396	256,024
Total liabilities and partners' capital	$ 962,288	$ 953,823