Related Party Transactions - Narrative (Details) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Amount of paid cash and received cash	$ 1,732,000		$ 4,757,000
Other tax benefits recorded as liability, current	521,000		3,282,000
Other tax benefits recorded as liability, noncurrent	28,078,000		9,460,000
Tax Receivable Agreement
Related Party Transaction [Line Items]
Payable under tax receivable agreement	28,600,000
Health Plan Intermediaries, LLC
Related Party Transaction [Line Items]
Amount of paid cash and received cash	4,500,000	$ 68,000
Estimated tax liabilities	0		$ 2,800,000
Tax Receivable Agreement
Related Party Transaction [Line Items]
Amount paid under agreement	$ 672,000