Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquid investments, original maturities	90 days
Perpetual growth rate for deferred consideration	1.50%	1.50%
Discount rate for deferred consideration	10.00%	10.00%
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gold forward-looking price range	$ 1,597	$ 1,535
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gold forward-looking price range	2,275	2,328
Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gold forward-looking price range	$ 1,775	$ 1,757