Accrued Liabilities and Deferred Credits (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accrued Liabilities And Deferred Credits [Line Items]
Accrued compensation	$ 3,366	$ 2,673
Deferred revenue	15,222	15,309
Membership deposits	7,778	8,426
Other accrued liabilities	6,505	5,651
Total accrued liabilities and deferred credits	35,721	34,911
Special Purpose Entities
Accrued Liabilities And Deferred Credits [Line Items]
Accrued interest expense for Senior Notes held by special purpose entity	$ 2,850	$ 2,852