Deferred Consideration - Additional Information (Detail) $ in Thousands	Mar. 31, 2021 USD ($) oz	Dec. 31, 2020 USD ($) oz
Business Acquisition [Line Items]
Deferred consideration	$ 227,146	$ 230,137
Deferred consideration, current	15,637	17,374
Deferred consideration, non-current	$ 211,509	$ 212,763
April 1, 2018 through March 31, 2058 [Member]
Business Acquisition [Line Items]
Fixed payment ounces of gold | oz	9,500	9,500
April 1, 2058 and Thereafter [Member]
Business Acquisition [Line Items]
Fixed payment ounces of gold | oz	6,333	6,333