Debt - 2021 Notes, 2022 Notes and 2024 Notes - Additional Information (Detail) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2020	Jun. 30, 2020 USD ($) d	Dec. 31, 2019
2021 Notes, 2022 Notes and 2024 Notes [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt instrument convertible, percentage of conversion price		130.00%
2021 Notes, 2022 Notes and 2024 Notes [Member] \| One Hundred Thirty Percent Applicable Conversion Price [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt instrument convertible consecutive trading days		20
2021 Notes, 2022 Notes and 2024 Notes [Member] \| One Hundred Thirty Percent Applicable Conversion Price [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Debt instrument convertible trading days		30
Recourse debt [Member] \| 1.25% Convertible Senior Notes due in 2021 ("2021 Notes") [Member]
Debt Instrument [Line Items]
Maturity date	2021-03	2021-03	2021-03
Difference between the aggregate principal and carrying value as mezzanine equity \| $		$ 44