Condensed consolidated statements of comprehensive income (loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income including non-controlling interests	$ 39,827	$ 30,418	$ 71,466	$ 53,912
Other comprehensive income (loss), net:
Unrealized gain on interest rate caps, net of tax	0	17	0	383
Foreign currency translation adjustments	103	(34)	157	(63)
Total other comprehensive income, net	103	(17)	157	320
Total comprehensive income including non-controlling interests	39,930	30,401	71,623	54,232
Less: total comprehensive income attributable to non-controlling interests	4,983	4,543	9,213	8,214
Total comprehensive income attributable to Planet Fitness, Inc.	$ 34,947	$ 25,858	$ 62,410	$ 46,018