Company's Debt Maturities on Calendar Year Basis (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Debt Instrument [Line Items]
Total	$ 1,435,498		$ 911,718
October 1 through December 31, 2013	15,313
2014	61,250
2015	61,250
2016	325,067
2017	61,250
Thereafter	911,368
Senior Secured Notes
Debt Instrument [Line Items]
Total	852,200		600,000
October 1 through December 31, 2013	15,313
2014	61,250
2015	61,250
2016	61,250
2017	61,250
Thereafter	591,887
1.50% Convertible Notes
Debt Instrument [Line Items]
Total	319,481	[1]
Thereafter	319,481	[1]
2.50% Convertible Notes
Debt Instrument [Line Items]
Total	263,817	[2]	254,718
2016	$ 263,817	[2]

[1] Reflects the net debt carrying amount of the 1.50% Convertible Notes in the consolidated balance sheet as of September 30, 2013, 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 September 30, 2013, in accordance with accounting for convertible notes. The principal amount owed to the holders of the 2.50% Convertible Notes is $300.0 million.