Summary of Significant Accounting Policies - Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employment Contracts [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	9 years
Employment Contracts [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	11 years
Trade Names [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	10 years
Trade Names [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	20 years
Regular Member [Member]
Finite-Lived Intangible Assets [Line Items]
Average member life (in months)	25 months	22 months	22 months