Details of One Point Five Zero Percent Convertible Notes Reflected on Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Net debt carrying amount	[1]	$ 800,842	$ 1,254,160
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018
Debt Instrument [Line Items]
Equity component carrying amount		48,767	48,767
Unamortized discount		2,285	17,531
Net debt carrying amount	[2]	$ 233,898	$ 277,518

[1] Carrying amounts include aggregate unamortized debt discount and debt issuance costs.

[2] During FY 2016, the Company repurchased a total of $104.9 million par value (of which $51.7 million and $53.2 million were purchased in June 2016 and July 2016, respectively) of the 1.50% Convertible Notes. During FY 2017, the Company repurchased a total of $58.9 million par value of the 1.50% Convertible Notes. See below for further details. On February 22, 2018, the Company exchanged $125 million of aggregate principal amount of 1.50% Convertible Notes for $125 million of aggregate principal amount of 5.75% Convertible Notes, and on March 14, 2018, the Company drew down $110 million under the Second Delayed Draw Term Loan and used those proceeds, along with cash on hand, to make a payment to the trustee under the indenture governing the 1.50% Convertible Notes to repay the remaining 1.50% Convertible Notes at maturity on March 15, 2018.