Goodwill and Intangible Assets - Finite-lived Intangible Assets and Related Accumulated Amortization (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2017	Dec. 31, 2016
Intangible Assets
Cost or Fair Value	$ 45,607	$ 9,485
Accumulated Amortization	(7,635)	(6,099)
Net	37,972	3,386
Trademarks and trade names
Intangible Assets
Cost or Fair Value	28,839
Accumulated Amortization	(420)
Net	$ 28,419
Useful lives (in years)	15 years
Membership and customer lists
Intangible Assets
Cost or Fair Value	$ 10,778	9,485
Accumulated Amortization	(7,118)	(6,099)
Net	3,660	$ 3,386
Websites
Intangible Assets
Cost or Fair Value	5,990
Accumulated Amortization	(97)
Net	$ 5,893
Useful lives (in years)	10 years
Weighted Average \| Membership and customer lists
Intangible Assets
Useful lives (in years)	5 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

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- References

No definition available.

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