Condensed consolidated statements of comprehensive income (loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income including non-controlling interests	$ 30,418	$ 18,004	$ 53,912	$ 35,870
Other comprehensive income (loss), net:
Unrealized gain on interest rate caps, net of tax	17	179	383	356
Foreign currency translation adjustments	(34)	13	(63)	5
Total other comprehensive (loss) income, net	(17)	192	320	361
Total comprehensive income including non-controlling interests	30,401	18,196	54,232	36,231
Less: total comprehensive income attributable to non-controlling interests	4,543	5,639	8,214	14,753
Total comprehensive income attributable to Planet Fitness, Inc.	$ 25,858	$ 12,557	$ 46,018	$ 21,478