OPERATING SEGMENT REPORTING - Summary of Reportable Operating Segments (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Segment Reporting
Revenue from gold and silver sales									$ 136,541,000	$ 104,789,000	$ 117,019,000
Depreciation and depletion									(23,798,000)	(22,910,000)	(24,753,000)
Gross profit (loss)	$ (5,897,000)	$ 344,000	$ 4,059,000	$ (4,986,000)	$ (13,687,000)	$ (701,000)	$ (8,875,000)	$ (3,685,000)	(6,480,000)	(26,948,000)	8,986,000
Advanced projects									(12,439,000)	(11,681,000)	(9,520,000)
Impairment loss on mineral property interests and plant and equipment (Note 8)									0	(83,805,000)
Loss from investment in Minera Santa Cruz S.A.									(7,533,000)	(1,517,000)	(8,754,000)
Other operating										(1,968,000)
Loss before income and mining taxes									(64,199,000)	(153,715,000)	(63,591,000)
Capital expenditures									36,033,000	13,925,000	30,270,000
United States Reportable Segment [Member]
Operating Segment Reporting
Depreciation and depletion									(8,502,000)	(11,785,000)	(10,934,000)
Gross profit (loss)									(3,288,000)	(21,366,000)	(701,000)
Advanced projects									(440,000)	(1,071,000)	(649,000)
Impairment loss on mineral property interests and plant and equipment (Note 8)										(83,805,000)
Other operating										(1,390,000)
Segment loss									(9,603,000)	(114,409,000)	(9,904,000)
Capital expenditures									2,416,000	4,821,000	18,806,000
Canada
Operating Segment Reporting
Depreciation and depletion									(15,296,000)	(10,883,000)	(13,271,000)
Gross profit (loss)									2,447,000	(4,070,000)	5,666,000
Advanced projects									(2,635,000)	(6,088,000)	(1,636,000)
Other operating										(578,000)
Segment loss									(15,205,000)	(17,186,000)	(21,749,000)
Capital expenditures									33,617,000	9,104,000	11,464,000
Mexico Reportable Segment [Member]
Operating Segment Reporting
Depreciation and depletion										(242,000)	(548,000)
Gross profit (loss)									(5,640,000)	(1,512,000)	4,021,000
Advanced projects									(4,345,000)	(4,522,000)	(7,235,000)
Segment loss									(9,999,000)	(6,547,000)	(3,214,000)
MSC
Operating Segment Reporting
Loss from investment in Minera Santa Cruz S.A.									(7,533,000)	(1,517,000)	(8,754,000)
Segment loss									(7,533,000)	(1,517,000)	(8,754,000)
Los Azules
Operating Segment Reporting
Advanced projects									(5,019,000)
Segment loss									(6,717,000)	(2,121,000)	(3,411,000)
Total Segment
Operating Segment Reporting
Depreciation and depletion									(23,798,000)	(22,910,000)	(24,753,000)
Gross profit (loss)									(6,481,000)	(26,948,000)	8,986,000
Advanced projects									(12,439,000)	(11,681,000)	(9,520,000)
Impairment loss on mineral property interests and plant and equipment (Note 8)										(83,805,000)
Loss from investment in Minera Santa Cruz S.A.									(7,533,000)	(1,517,000)	(8,754,000)
Other operating										(1,968,000)
Segment loss									(49,056,000)	(141,780,000)	(47,032,000)
General and Administrative and other									(15,143,000)	(11,935,000)	(16,559,000)
Gold and silver sales
Operating Segment Reporting
Revenue from gold and silver sales	$ 34,966,000	$ 37,129,000	$ 40,706,000	$ 23,740,000	$ 27,703,000	$ 27,395,000	$ 18,291,000	$ 31,400,000	136,541,000	104,789,000	117,019,000
Gold and silver sales | United States Reportable Segment [Member]
Operating Segment Reporting
Revenue from gold and silver sales									79,205,000	48,884,000	43,847,000
Gold and silver sales | Canada
Operating Segment Reporting
Revenue from gold and silver sales									50,704,000	41,452,000	50,058,000
Gold and silver sales | Mexico Reportable Segment [Member]
Operating Segment Reporting
Revenue from gold and silver sales									6,632,000	14,453,000	23,114,000
Gold and silver sales | Total Segment
Operating Segment Reporting
Revenue from gold and silver sales									136,541,000	104,789,000	117,019,000
Product [Member]
Operating Segment Reporting
Production costs applicable to sales									(119,223,000)	(108,827,000)	(83,280,000)
Product [Member] | United States Reportable Segment [Member]
Operating Segment Reporting
Production costs applicable to sales									(73,991,000)	(58,465,000)	(33,614,000)
Product [Member] | Canada
Operating Segment Reporting
Production costs applicable to sales									(32,961,000)	(34,639,000)	(31,121,000)
Product [Member] | Mexico Reportable Segment [Member]
Operating Segment Reporting
Production costs applicable to sales									(12,272,000)	(15,723,000)	(18,545,000)
Product [Member] | Total Segment
Operating Segment Reporting
Production costs applicable to sales									(119,224,000)	(108,827,000)	(83,280,000)
Exploration | United States Reportable Segment [Member]
Operating Segment Reporting
Production costs applicable to sales									(5,875,000)	(6,777,000)	(8,554,000)
Exploration | Canada
Operating Segment Reporting
Production costs applicable to sales									(15,017,000)	(6,450,000)	(25,779,000)
Exploration | Mexico Reportable Segment [Member]
Operating Segment Reporting
Production costs applicable to sales									(14,000)	(513,000)
Exploration | Los Azules
Operating Segment Reporting
Production costs applicable to sales									(1,698,000)	(2,121,000)	(3,411,000)
Exploration | Total Segment
Operating Segment Reporting
Production costs applicable to sales									$ (22,604,000)	$ (15,861,000)	$ (37,744,000)