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Contingencies and Capital Commitments (Narrative) (Details) S/ in Thousands | 1 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Dec. 31, 2018 USD ($) | Sep. 30, 2020 PEN (S/) | Sep. 30, 2020 USD ($) | Dec. 31, 2020 PEN (S/) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2017 | Jan. 31, 2020 USD ($)
Disclosure of other provisions [line items] |  |  |  |  |  |  |  |
Security bond |  |  |  |  |  |  |  | $ 1,539,000
Bank letter of guarantee |  |  |  |  |  |  |  | 8,394,000
Tax expense (income) |  |  |  |  | $ 37,402,000 | $ 20,175,000 |  |
SGM Royalty (as percentage) |  |  |  |  |  |  | 3.00% |
Proposal Of Cancelling Mining Concession [Member] |  |  |  |  |  |  |  |
Disclosure of other provisions [line items] |  |  |  |  |  |  |  |
Claimed Royalty |  |  |  |  |  |  |  | $ 30,000,000
PERU |  |  |  |  |  |  |  |
Disclosure of other provisions [line items] |  |  |  |  |  |  |  |
Tax expense (income) |  |  |  | S/ 4,343 | 1,199,000 |  |  |
Income tax interest and penalties |  |  |  | S/ 2,405 | 664,000 |  |  |
Payment of disputed amount |  | S/ 4,343 | $ 1,199,000 |  |  |  |  |
Mineral Properties [member] | Civil Work [Member] |  |  |  |  |  |  |  |
Disclosure of other provisions [line items] |  |  |  |  |  |  |  |
Capital commitments |  |  | 558,000 |  |  |  |  |
Mineral Properties [member] | Equipment Purchases [Member] |  |  |  |  |  |  |  |
Disclosure of other provisions [line items] |  |  |  |  |  |  |  |
Capital commitments |  |  | 386,000 |  |  |  |  |
Mineral Properties [member] | Other Services [Member] |  |  |  |  |  |  |  |
Disclosure of other provisions [line items] |  |  |  |  |  |  |  |
Capital commitments |  |  | $ 134,000 |  |  |  |  |
Caylloma Mine [Member] |  |  |  |  |  |  |  |
Disclosure of other provisions [line items] |  |  |  |  |  |  |  |
Undiscounted closure costs | $ 11,719,000 |  |  |  |  |  |  |
Progressive closure activities | 3,774,000 |  |  |  |  |  |  |
Final closure activities | 7,156,000 |  |  |  |  |  |  |
Post closure activities | $ 789,000 |  |  |  |  |  |  |
Guarantees with government current year |  |  |  |  | 9,933,000 |  |  |
San Jose Mine [Member] | Environmental obligations [Member] |  |  |  |  |  |  |  |
Disclosure of other provisions [line items] |  |  |  |  |  |  |  |
Bank letter of guarantee |  |  |  |  | $ 1,168,000 |  |  |
Number of letters of guarantee |  |  |  |  | 3 |  |  |

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