Company's Debt Maturities on Calendar Year Basis (Detail) - USD ($) $ in Thousands		Mar. 31, 2015		Dec. 31, 2014
Debt Instrument [Line Items]
Total		$ 1,486,312		$ 1,394,077
2015		45,843
2016		344,572
2017		61,123
2018		505,236
2019		61,123
Thereafter		468,415
Senior Secured Notes
Debt Instrument [Line Items]
Total		758,750		774,030
2015		45,843
2016		61,123
2017		61,123
2018		61,123
2019		61,123
Thereafter		468,415
1.50% Convertible Notes
Debt Instrument [Line Items]
Total		344,113	[1]	339,943
2018	[1]	344,113
2.50% Convertible Notes
Debt Instrument [Line Items]
Total		283,449	[2]	$ 280,104
2016	[2]	283,449
Variable Funding Notes
Debt Instrument [Line Items]
Total		100,000
2018		$ 100,000

[1] Reflects the net debt carrying amount of the 1.50% Convertible Notes in the consolidated balance sheet as of March 31, 2015, in accordance with accounting for convertible notes. The principal amount owed to the holders of the 1.50% Convertible Notes is $400.0 million.

[2] Reflects the net debt carrying amount of the 2.50% Convertible Notes in the consolidated balance sheet as of March 31, 2015, in accordance with accounting for convertible notes. The principal amount owed to the holders of the 2.50% Convertible Notes is $300.0 million.