Subsequent Events- Additional Information (Detail) - Elara [Member] $ in Millions	1 Months Ended
	Oct. 31, 2020 USD ($) board_member	Sep. 30, 2020
REA Group
Subsequent Event [Line Items]
Current ownership interest		13.50%
Subsequent Event
Subsequent Event [Line Items]
Number of board of directors | board_member	9
Cash payments to acquire additional interests	$ 34.5
Increase in equity interest	38.90%
Subsequent Event | Minimum
Subsequent Event [Line Items]
Ownership interest after acquisition	86.10%
Subsequent Event | Maximum
Subsequent Event [Line Items]
Ownership interest after acquisition	100.00%
Subsequent Event | REA Group
Subsequent Event [Line Items]
Number of board seats held | board_member	5
Cash payments to acquire additional interests	$ 34.5
Subsequent Event | REA Group | Minimum
Subsequent Event [Line Items]
Ownership interest after acquisition	47.20%
Consideration transferred	$ 50.0
Subsequent Event | REA Group | Maximum
Subsequent Event [Line Items]
Ownership interest after acquisition	61.10%
Consideration transferred	$ 70.0