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Shares Issued During Period, Shares Exchanged For Class A Common Stock

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Final price paid per share for the purchase of the targeted number of shares, determined by an average market price over a fixed period of time.

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Balance held at close of period in number of shares.

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Number of stock bought back by the entity at the exercise price or redemption price.

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Amount of stock repurchase plan authorized.

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Number of shares that have been repurchased and retired during the period.

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Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

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Stockholder's Equity - Additional Information (Detail) - USD ($)			3 Months Ended	6 Months Ended
	Apr. 30, 2019	Nov. 14, 2018	Jun. 30, 2019	Jun. 30, 2019	Nov. 13, 2018	Aug. 03, 2018
Class of Stock [Line Items]
Stock repurchase program, authorized amount						$ 500,000,000
Repurchase and retirement of common stock			$ 1,000	$ 1,000
Pla-Fit Holdings, LLC
Class of Stock [Line Items]
Number of shares exchanged				865,810
Holdings Units
Class of Stock [Line Items]
Number of shares exchanged				865,810
Investor \| Secondary Offering and Exchange
Class of Stock [Line Items]
Number of units held by owners (in shares)			83,994,635	83,994,635
Investor \| Pla-Fit Holdings, LLC \| Secondary Offering and Exchange
Class of Stock [Line Items]
Percentage of economic interest				90.70%
Continuing LLC Owners \| Secondary Offering and Exchange
Class of Stock [Line Items]
Number of units held by owners (in shares)			8,581,920	8,581,920
Continuing LLC Owners \| Pla-Fit Holdings, LLC \| Secondary Offering and Exchange
Class of Stock [Line Items]
Percentage of economic interest				9.30%
Holdings Units
Class of Stock [Line Items]
Shares exchanged for Class A common stock				1
Class A Common Stock
Class of Stock [Line Items]
Number of shares exchanged				865,810
Class A Common Stock \| Investor \| Secondary Offering and Exchange
Class of Stock [Line Items]
Number of units held by owners (in shares)			83,994,635	83,994,635
Class A Common Stock \| Investor \| Pla-Fit Holdings, LLC \| Secondary Offering and Exchange
Class of Stock [Line Items]
Percentage of voting interests acquired			90.70%	90.70%
Class B Common Stock
Class of Stock [Line Items]
Shares exchanged for Class A common stock				1
Number of shares exchanged				865,810
Class B Common Stock \| Continuing LLC Owners \| Secondary Offering and Exchange
Class of Stock [Line Items]
Number of units held by owners (in shares)			8,581,920	8,581,920
Class B Common Stock \| Continuing LLC Owners \| Pla-Fit Holdings, LLC \| Secondary Offering and Exchange
Class of Stock [Line Items]
Percentage of voting interests acquired			9.30%	9.30%
ASR Agreement
Class of Stock [Line Items]
Stock repurchase program, authorized amount					$ 300,000,000
Repurchase and retirement of common stock	$ 60,000,000	$ 240,000,000
ASR Agreement \| Class A Common Stock
Class of Stock [Line Items]
Stock repurchased (in shares)	524,124	4,607,410
Weighted average cost per share (in dollars per share)	$ 58.46