Subsequent Events - Additional Information (Detail)	Apr. 15, 2019 USD ($)	Mar. 14, 2018 USD ($)	Feb. 22, 2018 USD ($) d	Feb. 12, 2018 USD ($)	Jan. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Nov. 24, 2017 USD ($)	Oct. 27, 2017 USD ($)	Aug. 02, 2017 USD ($)	Jul. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016	Jul. 31, 2016 USD ($)	Dec. 31, 2015	Mar. 18, 2013 USD ($)
Subsequent Event [Line Items]
Principal amount of long term debt								$ 240,700,000			$ 0
Complex Media Inc.
Subsequent Event [Line Items]
Remaining escrow balance related to sale of ownership interest										$ 3,700,000			$ 3,700,000
Deutsche Bank AG
Subsequent Event [Line Items]
Principal amount of long term debt								$ 300,000,000	$ 300,000,000
Estimated principal payments							$ 12,000,000
Convertible Notes | Deutsche Bank AG
Subsequent Event [Line Items]
Debt instrument, interest rate, stated percentage						1.50%
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%
Principal amount of long term debt						$ 236,200,000									$ 400,000,000
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Deutsche Bank AG
Subsequent Event [Line Items]
Remaining escrow balance related to sale of ownership interest						$ 300,000,000
Convertible Notes | 5.75% Senior Subordinated Notes Due August 2023 | Scenario, Forecast
Subsequent Event [Line Items]
Obligation shares of common stock for payments In lieu of cash	$ 0
Subsequent Event
Subsequent Event [Line Items]
Debt instrument, maturity date			Mar. 15, 2018
Subsequent Event | Complex Media Inc.
Subsequent Event [Line Items]
Remaining escrow balance related to sale of ownership interest					$ 1,000,000
Subsequent Event | 5.75% Senior Subordinated Notes Due August 2023 | Deutsche Bank AG
Subsequent Event [Line Items]
Debt instrument, interest rate, stated percentage				5.75%
Subsequent Event | 5.75% Senior Subordinated Notes Due August 2023 | Maximum | Deutsche Bank AG
Subsequent Event [Line Items]
Estimated principal payments				$ 6,100,000
Subsequent Event | 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%
Principal amount of long term debt			$ 125,000,000
Debt instrument, maturity date			Mar. 15, 2018
Proceeds from convertible note		$ 110,000
Subsequent Event | Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Minimum
Subsequent Event [Line Items]
Reduction in outstanding principal amount			$ 100,000,000
Subsequent Event | Convertible Notes | 5.75% Senior Subordinated Notes Due August 2023
Subsequent Event [Line Items]
Debt instrument convertible conversion price as percentage upon automatic conversion			5.75%
Debt instrument convertible conversion price as percentage upon mandatory conversion			5.75%
Debt instrument, convertible, threshold trading days | d			10
Debt instrument, convertible, threshold consecutive trading days | d			30
Debt instrument, redemption price, percentage			100.00%
Debt instrument, redemption, description			Each holder will have the right, at its option, to require the Company to repurchase for cash all or a portion of such holder’s 5.75% Convertible Notes at a fundamental change purchase price equal to 100% of the principal amount of the 5.75% Convertible Notes to be repurchased, together with interest accrued and unpaid to, but excluding, the fundamental change purchase date.
Volume weighted average price description			If the Company elects to pay all or a portion of a Conversion Make-Whole Payment in shares of common stock, the number of shares of common stock payable will be equal to the applicable Conversion Make-Whole Payment divided by the average of the 10 individual volume-weighted average prices for the 10-trading day period immediately preceding the applicable conversion date.
Debt instrument, restrictive covenants			The Company will be subject to certain restrictive covenants pursuant to the 5.75% Convertible Note Indenture, including limitations on (i) liens, (ii) indebtedness, (iii) asset sales, (iv) restricted payments and investments, (v) prepayments of indebtedness and (vi) transactions with affiliates.
Subsequent Event | Convertible Notes | 5.75% Senior Subordinated Notes Due August 2023 | Scenario, Plan
Subsequent Event [Line Items]
Debt instrument, interest rate, stated percentage			5.75%
Principal amount of long term debt			$ 125,000,000