Company's Debt Maturities on Calendar Year Basis (Detail) - USD ($) $ in Thousands		Sep. 30, 2018		Dec. 31, 2017
Debt Instrument [Line Items]
Total		$ 697,147
October 1 through December 31, 2018		11,637
2019		54,263
2020		156,227
2021		61,977
2022		162,456
Thereafter		250,587
Senior Secured Notes
Debt Instrument [Line Items]
Total		376,154		$ 408,174
October 1 through December 31, 2018		10,673
2019		42,693
2020		42,693
2021		42,693
2022		42,693
Thereafter		194,709
Convertible Notes | 5.75% Senior Subordinated Notes Due August 2023
Debt Instrument [Line Items]
Total	[1],[2]	55,878
Thereafter	[2]	55,878
Variable Funding Notes
Debt Instrument [Line Items]
Total		94,250	[3]	$ 91,363
2020	[3]	94,250
Senior Secured Term Loan
Debt Instrument [Line Items]
Total	[4]	170,865
October 1 through December 31, 2018	[4]	964
2019	[4]	11,570
2020	[4]	19,284
2021	[4]	19,284
2022	[4]	$ 119,763

[1] On February 12, 2018, the Company entered into the Exchange Agreements and consummated the Note Exchange on February 22, 2018, pursuant to which the Company exchanged approximately $125.0 million aggregate principal amount of its 1.50% Convertible Notes for 5.75% Convertible Notes issued by the Company in an aggregate principal amount of approximately $125.0 million. See below for further details.

[2] Reflects the debt carrying amount which is accounted for under the Fair Value Option in the unaudited condensed consolidated balance sheet as of September 30, 2018. The actual principal outstanding balance of the 5.75% Convertible Notes is $111.0 million as of September 30, 2018.

[3] Reflects the net debt carrying amount, effected by the outstanding balance of the original issue discount, in the unaudited condensed consolidated balance sheet as of September 30, 2018. The actual principal outstanding balance of the Variable Funding Notes is $100.0 million as of September 30, 2018.

[4] Reflects the net debt carrying amount, effected by the outstanding balance of the original issue discount, in the unaudited condensed consolidated balance sheet as of June 30, 2018. The actual principal outstanding balance of the Senior Secured Term Loan is $190.4 million as of September 30, 2018.