Subsequent Events - Additional Information (Detail) - USD ($)				3 Months Ended	9 Months Ended
	Nov. 24, 2017	Oct. 31, 2017	Oct. 27, 2017	Sep. 30, 2017	Sep. 30, 2017	Jul. 31, 2019	Mar. 15, 2018	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Mar. 18, 2013	May 23, 2011
Subsequent Event [Line Items]
Principal amount of long term debt								$ 0
Subsequent Event | Amended and Restated 2016 Omnibus Incentive Plan
Subsequent Event [Line Items]
Number of additional common stock shares approved for issuance under Incentive Plan		1,900,000
Deutsche Bank AG | Subsequent Event
Subsequent Event [Line Items]
Cash from escrow deposit returned to Lenders			$ 231,000,000
Principal amount of long term debt			$ 300,000,000
Total leverage ratio			4.50%
Net proceeds from Permitted Capital Raising Transactions			$ 100,000,000
Estimated maximum aggregated payment amount on account of FLEX	$ 12,000,000
Deutsche Bank AG | Subsequent Event | Maximum
Subsequent Event [Line Items]
Aggregate amount of term loan facility			$ 165,700,000
Total leverage ratio			5.75%
Convertible Notes | Deutsche Bank AG
Subsequent Event [Line Items]
Payment from Escrow Account to acquire convertible notes					$ 59,200,000
Debt instrument, interest rate, stated percentage				1.50%	1.50%
Convertible Notes | Deutsche Bank AG | Subsequent Event
Subsequent Event [Line Items]
Cash from escrow deposit returned to Lenders			$ 231,000,000
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018
Subsequent Event [Line Items]
Debt instrument, interest rate, stated percentage				1.50%	1.50%				1.50%	1.50%	1.50%	2.50%
Principal amount of long term debt				$ 236,200,000	$ 236,200,000						$ 400,000,000	$ 300,000,000
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Deutsche Bank AG
Subsequent Event [Line Items]
Payment from Escrow Account to acquire convertible notes				$ 59,200,000
Debt instrument, interest rate, stated percentage				1.50%	1.50%
Senior Secured Term Loan Due 2022 | Deutsche Bank AG | Subsequent Event
Subsequent Event [Line Items]
Principal amount of long term debt			300,000,000
Aggregate amount of term loan facility			$ 225,000,000
Total leverage ratio			4.75%
Amortization rate per annum			2.00%
Senior Secured Term Loan Due 2022 | Deutsche Bank AG | Subsequent Event | Maximum | Scenario, Forecast
Subsequent Event [Line Items]
Amortization rate per annum						10.00%
Senior Secured Term Loan Due 2022 | Deutsche Bank AG | Subsequent Event | Minimum
Subsequent Event [Line Items]
Amortization rate per annum			2.00%
New Senior Secured Delayed Draw Term Loan Facility | Deutsche Bank AG | Subsequent Event | Maximum
Subsequent Event [Line Items]
Aggregate amount of term loan facility			$ 165,700,000
First Delayed Draw Term Loan | Deutsche Bank AG | Subsequent Event
Subsequent Event [Line Items]
Aggregate amount of term loan facility			$ 25,000,000
Second Delayed Draw Term Loan | Deutsche Bank AG | Scenario, Forecast
Subsequent Event [Line Items]
Aggregate amount of term loan facility							$ 140,700,000
New Senior Secured Term Loan | Deutsche Bank AG | Scenario, Forecast
Subsequent Event [Line Items]
Amortization rate per annum						10.00%
New Senior Secured Term Loan | Deutsche Bank AG | Subsequent Event
Subsequent Event [Line Items]
Total leverage ratio			5.75%
Net proceeds from Permitted Capital Raising Transactions			$ 100,000,000