Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue		$ 785,636	$ 832,828	$ 785,461
COSTS AND EXPENSES
Amortization		111,626	128,315	131,387
General and administrative		39,460	40,399	33,722
Pre-development, reclamation, and other		41,287	48,678	55,654
Total costs and expenses		825,527	780,100	703,741
OTHER INCOME (EXPENSE), NET
Gain (Loss) on Extinguishment of Debt		0	(9,173)	0
Fair value adjustments, net, pretax		(66,668)	(543)	7,601
Interest expense, net of capitalized interest		(23,861)	(16,451)	(20,708)
Other, net		(66,971)	22,925	5,941
Total other income (expense), net		(23,558)	(49,092)	(19,048)
Income (loss) before income and mining taxes		(63,449)	3,636	62,672
Income and mining tax (expense) benefit		(14,658)	(34,958)	(37,045)
NET INCOME (LOSS)		(78,107)	(31,322)	25,627
OTHER COMPREHENSIVE INCOME (LOSS), Net of Tax:
Unrealized gain (loss) on hedger, net of tax		37,445	22,783	(12,434)
Reclassification adjustments for realized (gain) loss on cash flow hedges		23,890	12,859	(1,434)
Other comprehensive income (loss)		13,555	9,924	(11,000)
COMPREHENSIVE INCOME (LOSS)		$ (64,552)	$ (21,398)	$ 14,627
Basic EPS
Earnings Per Share, Basic		$ (0.28)	$ (0.13)	$ 0.11
Diluted EPS
Earnings Per Share, Diluted		$ (0.28)	$ (0.13)	$ 0.11
Accumulated Deficit [Member]
OTHER INCOME (EXPENSE), NET
NET INCOME (LOSS)		$ (78,107)	$ (31,322)	$ 25,627
Product
COSTS AND EXPENSES
Costs applicable to sales	[1]	606,530	511,539	440,335
Mineral, Exploration
COSTS AND EXPENSES
Costs applicable to sales		$ 26,624	$ 51,169	$ 42,643

[1] Excludes amortization.