Net Carrying Amount of Debt (Detail) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total debt	[1]	$ 1,254,160	$ 1,449,392
Unamortized debt issuance costs	[2]	(20,048)	(15,016)
Less current maturities		160,435	61,123
Total long-term debt		1,093,725	1,388,269
Senior Secured Notes
Debt Instrument [Line Items]
Total debt		651,784	712,907
Less current maturities		95,300	95,300
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018
Debt Instrument [Line Items]
Total debt	[3]	277,518	357,453
Convertible Notes | 2.50% Senior Subordinated Notes Due June 2016
Debt Instrument [Line Items]
Total debt	[4]		294,048
Variable Funding Notes
Debt Instrument [Line Items]
Total debt		100,000	$ 100,000
Senior Secured Term Loan
Debt Instrument [Line Items]
Total debt	[5]	$ 244,906

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

[2] During the first quarter of FY 2016, the Company retrospectively adopted ASU 2015-03, “Simplifying the Presentation of Debt Issuance Costs”. Refer to Note 1 for further details.

[3] 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. See below for further details.

[4] In April 2016, the Company repurchased $143.9 million par value of the 2.50% Convertible Notes. Upon maturity of the notes on June 1, 2016, the Company repaid the remaining outstanding balance of $156.1 million in cash. See below for further details.

[5] In December 2016, the Company made a mandatory principal prepayment of $28.7 million on its Senior Secured Term Loan. See below for further details.