Revenue from club operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Income and Expenses [Abstract]
Membership dues									$ 309,096	$ 343,185	$ 358,761
Initiation and processing fees									13,644	12,044	14,392
Personal training revenue									73,191	70,338	66,367
Other ancillary club revenue									22,138	22,304	24,720
Total club revenue									418,069	447,871	464,240
Fees and other revenue									6,254	5,971	5,985
Total revenue	$ 100,839	$ 103,764	$ 108,296	$ 111,424	$ 109,721	$ 112,521	$ 115,697	$ 115,903	$ 424,323	$ 453,842	$ 470,225