Equity Method Investments (Details) - USD ($)				3 Months Ended		9 Months Ended
	Feb. 07, 2018	Jul. 24, 2017	Jul. 25, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Equity method investments				$ 47,996,000		$ 47,996,000		$ 54,606,000
Net revenues				505,289,000	$ 385,267,000	1,432,472,000	$ 1,052,090,000
Loan repayment from equity investee						30,000,000	6,000,000
SDC
Schedule of Equity Method Investments [Line Items]
Ownership			17.00%
Payments to acquire		$ 12,800,000	$ 46,700,000
Additional ownership acquired		2.00%
Due from related parties				12,500,000		12,500,000		$ 14,300,000
Net revenues				$ 8,100,000	$ 10,600,000	$ 22,000,000	$ 14,200,000
SDC
Schedule of Equity Method Investments [Line Items]
Loan repayment from equity investee	$ 30,000,000
Maximum | SDC
Schedule of Equity Method Investments [Line Items]
Loan receivable		$ 30,000,000.0