Summary of Significant Accounting Policies - AOCI and Concentrations of Credit Risk (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) club	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)
Accounting Policies [Line Items]
Number of stores | club	152
Foreign currency translation adjustment	$ (165)	$ (545)	$ 68
Foreign currency translation adjustment, tax	0	0	49
Cash and cash equivalents held at two financial institutions	64,824
Cash and cash equivalents	$ 76,217	$ 93,452	$ 73,598	$ 37,758
Switzerland Clubs [Member]
Accounting Policies [Line Items]
Number of stores | club	3