Deferred Consideration - Additional Information (Detail) $ in Thousands	9 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) oz
Business Acquisition [Line Items]
Deferred consideration	$ 161,540	$ 173,024
Deferred consideration, current	11,765	13,953
Deferred consideration, non-current	$ 149,775	$ 159,071
Discount rate used to value the deferred consideration	10.00%	10.00%
Perpetual Growth Rate	1.50%	1.50%
April 1, 2018 through March 31, 2058 [Member]
Business Acquisition [Line Items]
Fixed payment ounces of gold | oz		9,500
April 1, 2058 and Thereafter [Member]
Business Acquisition [Line Items]
Fixed payment ounces of gold | oz		6,333