Schedule of Debt Obligations (Detail) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total debt	[1]	$ 1,013,318	$ 1,254,160
Unamortized debt issuance costs		(13,710)	(20,048)
Less current maturities		553,549	160,435
Total long-term debt		459,769	1,093,725
Senior Secured Notes
Debt Instrument [Line Items]
Total debt		418,847	651,784
Less current maturities		42,700	95,300
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018
Debt Instrument [Line Items]
Total debt	[2]	230,929	277,518
Variable Funding Notes
Debt Instrument [Line Items]
Total debt	[3]	90,429	100,000
Senior Secured Term Loan
Debt Instrument [Line Items]
Total debt	[4]		$ 244,906
2017 Senior Secured Term Loan Due 2022
Debt Instrument [Line Items]
Total debt	[5]	$ 286,823

[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 the Current Quarter, the Company repurchased a total of $58.9 million par value of the 1.50% Convertible Notes. See below for further details.

[3] On August 18, 2017, the Company entered into an amendment of its Variable Funding Note which extended the anticipated repayment date for the Variable Funding Notes from January 2018 to January 2020. See below for further details.

[4] On June 30, 2017, the Company repaid the remaining outstanding principal balance of the Senior Secured Term Loan and accordingly, the Company wrote off the remaining portion of the deferred financing costs and original issue discount associated with the debt facility. See below for further details.

[5] On August 2, 2017, the Company entered into a long-term refinancing arrangement with Deutsche Bank AG for an aggregate principal amount of $300 million. See below for further details.