Stockholder's Equity - Additional Information (Detail) - USD ($)					1 Months Ended	6 Months Ended
	Jun. 28, 2016	Aug. 11, 2015	Aug. 05, 2015	Jun. 22, 2015	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Aug. 06, 2015
Class Of Stock [Line Items]
Convertible stock, conversion description						Following the Merger and the Reclassification, the Company and the Continuing LLC Owners entered into an exchange agreement under which the Continuing LLC Owners (or certain permitted transferees thereof) have the right, from time to time and subject to the terms of the exchange agreement, to exchange their Holdings Units, along with a corresponding number of shares of Class B common stock, for shares of Class A common stock (or cash at the option of the Company) on a one-for-one basis, subject to customary conversion rate adjustments for stock splits, stock dividends, reclassifications and similar transactions.
Pla-Fit Holdings, LLC [Member]
Class Of Stock [Line Items]
Number of units held by owners	7,891,160				7,891,160	7,891,160
Continuing LLC Owners [Member] | IPO and Secondary Offering [Member]
Class Of Stock [Line Items]
Percentage of economic interest	54.90%
Number of units held by owners	54,079,804
Class A Common Stock [Member]
Class Of Stock [Line Items]
Number of stock issued during period	11,500,000				11,500,000
Common stock, shares outstanding		36,597,985			44,489,000	44,489,000	36,598,000	0
Share price	$ 16.50				$ 16.50	$ 16.50
Proceeds from sale of shares	$ 0
Class A Common Stock [Member] | Direct TSG Investors [Member]
Class Of Stock [Line Items]
Number of shares converted				26,106,930
Number of stock issued during period	3,608,840	5,033,945			3,608,840
Class A Common Stock [Member] | Direct TSG Investors [Member] | IPO and Secondary Offering [Member]
Class Of Stock [Line Items]
Number of stock issued during period	17,464,145
Percentage of economic interest	17.70%
Percentage of voting power	17.70%
Class A Common Stock [Member] | Continuing LLC Owners [Member]
Class Of Stock [Line Items]
Number of stock issued during period	7,891,160				7,891,160
Class A Common Stock [Member] | Continuing LLC Owners [Member] | Pla-Fit Holdings, LLC [Member] | IPO [Member]
Class Of Stock [Line Items]
Number of stock issued during period		10,491,055
Aggregate amount of units issued		$ 156,946,000
Class A Common Stock [Member] | Investor | IPO and Secondary Offering [Member]
Class Of Stock [Line Items]
Number of stock issued during period	27,025,000
Percentage of economic interest	27.40%
Percentage of voting power	27.40%
Class B Common Stock [Member]
Class Of Stock [Line Items]
Common stock, shares outstanding					54,080,000	54,080,000	62,112,000	0
Class B Common Stock [Member] | Continuing LLC Owners [Member]
Class Of Stock [Line Items]
Number of stock issued during period			72,602,810
Common stock dividend and voting rights description						The shares of Class B common stock have no rights to dividends or distributions, whether in cash or stock, but entitle the holder to one vote per share on matters presented to stockholders of the Company.
Number of shares exchanged	7,891,160				7,891,160	7,891,160
Class B Common Stock [Member] | Continuing LLC Owners [Member] | IPO and Secondary Offering [Member]
Class Of Stock [Line Items]
Percentage of voting power	54.90%
Number of units held by owners	54,079,804
Class B Common Stock [Member] | Continuing LLC Owners [Member] | Pla-Fit Holdings, LLC [Member]
Class Of Stock [Line Items]
Number of stock issued during period			72,602,810
Merger Agreement [Member] | Class A Common Stock [Member] | Direct TSG Investors [Member]
Class Of Stock [Line Items]
Number of shares converted				26,106,930