Revenue from club operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Income and Expenses [Abstract]
Membership dues									$ 343,185	$ 358,761	$ 366,044
Joining fees									12,044	14,392	11,595
Personal training revenue									70,338	66,367	65,641
Other club ancillary revenue									22,304	24,720	29,897
Total club revenue									447,871	464,240	473,177
Fees and other revenue									5,971	5,985	5,804
Total revenue	$ 109,721	$ 112,521	$ 115,697	$ 115,903	$ 113,907	$ 117,042	$ 120,112	$ 119,164	$ 453,842	$ 470,225	$ 478,981