Goodwill and Intangible Assets - Finite-lived Intangible Assets and Related Accumulated Amortization (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Intangible Assets
Cost or Fair Value	$ 47,465	$ 47,349
Accumulated Amortization	(9,758)	(8,642)
Net	37,707	38,707
Trademarks and trade names
Intangible Assets
Cost or Fair Value	14,303	14,187
Accumulated Amortization	(549)	(312)
Net	$ 13,754	13,875
Useful lives (in years)	15 years
Membership and customer lists
Intangible Assets
Cost or Fair Value	$ 28,988	28,988
Accumulated Amortization	(8,969)	(8,194)
Net	20,019	20,794
Websites
Intangible Assets
Cost or Fair Value	4,174	4,174
Accumulated Amortization	(240)	(136)
Net	$ 3,934	$ 4,038
Useful lives (in years)	10 years
Weighted Average \| Membership and customer lists
Intangible Assets
Useful lives (in years)	5 years

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

+ Details

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- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

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- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

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- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

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- References

No definition available.

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