Loan Facilities - Additional Information (Details) - USD ($)		3 Months Ended		6 Months Ended			12 Months Ended	45 Months Ended
	Oct. 12, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2018	Sep. 30, 2022	Dec. 31, 2017
Line of Credit Facility [Line Items]
Secured loan payable		$ 331,451,000			$ 331,451,000				$ 339,048,000
Interest expense		5,594,000	$ 789,000		10,855,000	$ 1,608,000
Recapitalization Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Unamortized discount (premium) and debt issuance costs, net	$ 11,500,000
Unamortized discount	1,750,000
Deferred financing costs	9,800,000
Amortization of debt issuance costs and discounts		600,000			$ 1,200,000
Long-term debt, weighted average interest rate, over time (percent)					5.55%
Recapitalization Credit Agreement | Secured Debt | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)					2.75%
Recapitalization Credit Agreement | Secured Debt | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)					3.75%
Revolving Credit Facility | Secured Debt
Line of Credit Facility [Line Items]
Covenant, leverage ratio, excess borrowings, minimum		12,500,000
Revolving Credit Facility | Recapitalization Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity	$ 20,000,000
Debt instrument term (years)	3 years
Secured loan payable		0			$ 0				0
Term Loan | Recapitalization Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity	$ 350,000,000
Debt instrument term (years)	5 years
Secured loan payable		$ 331,500,000			331,500,000				$ 339,000,000
Quarterly payment of principal					$ 8,750,000
Scenario, Forecast | Term Loan | Recapitalization Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Quarterly payment of principal				$ 4,375,000				$ 8,750,000
Line of credit facility, annual principal payment								$ 35,000,000
Annual prepayment of principal, period of time required before year end							90 days
Annual principal payment, percentage of excess cash flow							50.00%
Prepaid, Refinanced, or Repriced Prior to April 12, 2019 | Term Loan | Recapitalization Credit Agreement | Secured Debt
Line of Credit Facility [Line Items]
Debt instrument, redemption price, percentage					101.00%
UNITED STATES | Term Loan | Secured Debt
Line of Credit Facility [Line Items]
Capital stock Of subsidiary, percentage					100.00%
Non-US | Term Loan | Secured Debt
Line of Credit Facility [Line Items]
Capital stock Of subsidiary, percentage					65.00%