Consolidated statements of comprehensive income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income including non-controlling interests	$ 103,162	$ 55,601	$ 71,247
Net income including non-controlling interests
Unrealized gain (loss) on interest rate caps, net of tax	989	1,143	(78)
Foreign currency translation adjustments	(200)	26	(72)
Total other comprehensive income (loss), net	789	1,169	(150)
Total comprehensive income including non-controlling interests	103,951	56,770	71,097
Less: total comprehensive income attributable to non-controlling interests	15,189	22,707	49,560
Total comprehensive income attributable to Planet Fitness, Inc.	$ 88,762	$ 34,063	$ 21,537