Summary of Significant Accounting Policies - Revenue Recognition (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) club session	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Summary of Significant Accounting Policies - Revenue Recognition [Line Items]
Usage fee revenue	$ 1,015	$ 719	$ 2,248
Initiation and processing fees, period of recognition (in months)	12 months
Annual membership fees, amortization period (in months)	12 months
Deferred membership costs	$ 1,092	3,029
Unused and expired personal training sessions	$ 15,079	14,968
Personal training, recognition period (in months)	3 months
Bonds outstanding pursuant to various state consumer protection laws	$ 3,112	3,900
Managed Sites [Member]
Summary of Significant Accounting Policies - Revenue Recognition [Line Items]
Managed university sites | club	3
Managed sites | club	8
Revenues	$ 1,892	$ 1,802	$ 1,502
Minimum [Member]
Summary of Significant Accounting Policies - Revenue Recognition [Line Items]
Number of personal training sessions per month | session	4
Maximum [Member]
Summary of Significant Accounting Policies - Revenue Recognition [Line Items]
Number of personal training sessions per month | session	12
Regular Member [Member]
Summary of Significant Accounting Policies - Revenue Recognition [Line Items]
Average member life (in months)	25 months	22 months	22 months