Accounts Payable and Accrued Liabilities - Additional Information (Detail) - Basic Management Inc And LandWell - Real Estate Management And Development - Deferred Payment $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2014	Dec. 31, 2013 USD ($)
Accounts Payable And Accrued Liabilities [Line Items]
Interest rate			3.00%
Early repayment of obligation		$ 9.6
Recognized accretion expense	$ 0.2	$ 0.8
Debt instrument principal amount	$ 1.5
Face Value
Accounts Payable And Accrued Liabilities [Line Items]
Business combination consideration transferred, deferred payment obligation				$ 11.1
Present Value | Measurement Input, Discount Rate
Accounts Payable And Accrued Liabilities [Line Items]
Discount rate			3