Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Thousands				3 Months Ended	9 Months Ended
	Apr. 06, 2021 USD ($) $ / shares shares	Jul. 01, 2020 $ / shares shares	Jun. 10, 2020 shares	Sep. 30, 2020 USD ($) shares	Sep. 30, 2021 USD ($) day $ / shares shares	Sep. 30, 2020 USD ($)	Dec. 31, 2020 $ / shares shares	Jun. 11, 2020 $ / shares shares
Class of Stock [Line Items]
Common stock, par value (in dollars per share) | $ / shares					$ 0.01		$ 0.01	$ 0.01
Common stock, shares authorized (in shares)					550,000,000		550,000,000	550,000,000
Preferred stock, shares authorized (in shares)					10,000,000		10,000,000	10,000,000
Common stock, shares outstanding (in shares)					126,190,351		126,803,096	91,849,909
Common stock, shares, issued, subject to certain lock-up and forfeiture arrangements (in shares)								3,437,500
Common stock, shares, outstanding, subject to certain lock-up and forfeiture arrangements (in shares)								3,437,500
Preferred stock, par value (in dollars per share) | $ / shares					$ 0.01		$ 0.01	$ 0.01
Class of warrant or right, outstanding (in shares)								9,166,659
Share price (in dollars per share) | $ / shares								$ 18.00
Proceeds from stock warrant exercises | $					$ 0	$ 88,042
Common stock repurchased (in shares)	612,745
Common stock repurchased | $	$ 20,000
Public Stock Offering
Class of Stock [Line Items]
Sale of stock, maximum shares authorized (in shares)	9,000,000
Sale of stock, price per share (in dollars per share) | $ / shares	$ 34.00
Over-Allotment Option
Class of Stock [Line Items]
Sale of stock, maximum shares authorized (in shares)	1,350,000
Sale of stock, over-allotment purchase period	30 days
Public Warrants
Class of Stock [Line Items]
Class of warrant or right, outstanding (in shares)								9,166,659
Class of warrant or right exercise price (in dollars per share) | $ / shares		$ 11.50						$ 11.50
Class of warrant or right threshold trading days for exercise					30 days
Class of warrant or right, redemption price (in dollars per share) | $ / shares								$ 0.01
Class of warrant or right, minimum notice period for redemption					30 days
Class of warrant or right, redemption, threshold trading days | day					30
Class of warrant or right, exercised (in shares)				7,882,163
Proceeds from stock warrant exercises | $				$ 88,000
Minimum | Public Warrants
Class of Stock [Line Items]
Class of warrant or right, redemption, threshold consecutive trading days | day					20
Common Stock
Class of Stock [Line Items]
Class of warrant or right, number of securities called by warrants or rights (in shares)		9,166,659
Nebula Holdings LLC
Class of Stock [Line Items]
Business combination, number of shares issued (in shares)			51,909,655
Nebula Holdings LLC | Earnout Consideration
Class of Stock [Line Items]
Business combination, number of shares issued (in shares)			22,500,000
Nebula Holdings LLC | Earnout Consideration | Nebula Equity Holders
Class of Stock [Line Items]
Business combination, number of shares issued (in shares)			1,250,000
Nebula Holdings LLC | Maximum | Earnout Consideration
Class of Stock [Line Items]
Business combination, number of shares issued (in shares)		23,750,000
Nebula Holdings LLC | Common Stock
Class of Stock [Line Items]
Number of shares registered for issuance (in shares)		52,916,659