Stockholders' Equity - Share Activity by Class of Stock (Details) - shares	9 Months Ended
Sep. 30, 2021	Dec. 31, 2020
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	78,572,110
Shares issued (in shares)	0
Restricted share award net share settlement (in shares)	(176,194)
Delivery of shares underlying RSUs (in shares)	1,074
Holdings Common Unit Exchanges (in shares)	(97,600)
Ending balance (in shares)	79,039,639
Class A Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	63,131,007
Holdings common unit exchanges (in shares)	(653,741)
Restricted share award net share settlement (in shares)	(176,194)
Delivery of shares underlying RSUs (in shares)	1,074
Holdings Common Unit Exchanges (in shares)	(97,600)
Ending balance (in shares)	65,215,891
Class B Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	4,457,958
Holdings common unit exchanges (in shares)	(186,657)
Restricted share award net share settlement (in shares)	0
Delivery of shares underlying RSUs (in shares)	0
Holdings Common Unit Exchanges (in shares)	0
Ending balance (in shares)	3,632,687
Class C Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	10,983,145
Holdings common unit exchanges (in shares)	(467,084)
Restricted share award net share settlement (in shares)	0
Delivery of shares underlying RSUs (in shares)	0
Holdings Common Unit Exchanges (in shares)	0
Ending balance (in shares)	10,191,061
Restricted Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued (in shares)	(740,249)
Unvested - Number of awards (in shares)	5,251,822	5,293,642
Restricted Stock \| Class A Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued (in shares)	(740,249)
Restricted Stock \| Class B Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued (in shares)	0
Restricted Stock \| Class C Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued (in shares)	0
Restricted Stock Units RSUs
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Delivery of shares underlying RSUs (in shares)	1,074
Restricted stock units outstanding (in shares)	327,713	304,570
Restricted Stock Units RSUs \| Class A Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Delivery of shares underlying RSUs (in shares)	1,074
Performance Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued in period (in shares)	135,230
Unvested - Number of awards (in shares)	135,230	60,000
Performance Shares \| Potential Performance Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unvested - Number of awards (in shares)	165,233
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Holdings common unit exchanges (in shares)	0
Follow On Offering
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued (in shares)	0
Follow On Offering \| Class A Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued (in shares)	(963,614)
Follow On Offering \| Class B Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued (in shares)	(638,614)
Follow On Offering \| Class C Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued (in shares)	(325,000)

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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