Derivative Financial Instruments - Summary of Net Currency Units Outstanding (Detail)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 GBP (£)	Mar. 31, 2020 NZD ($)	Mar. 31, 2020 EUR (€)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 GBP (£)	Dec. 31, 2019 NZD ($)	Dec. 31, 2019 EUR (€)
Offsetting [Abstract]
Net currency units outstanding	$ 2,800,000	£ 3,700,000	$ 16,000,000	€ 1,200,000	$ 6,200,000	£ 3,700,000	$ 16,000,000	€ 1,200,000