Schedule of Long-Term Debt (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2012
Debt Instrument [Line Items]
Revolving credit facility, maturity period	2016
Percentage of capital stock of foreign direct subsidiary secured by pledges	66.00%
7 5/8% Senior Notes | Long Term Borrowings
Debt Instrument [Line Items]
Interest percentage	7.625%
3 1/2% Convertible Senior Notes
Debt Instrument [Line Items]
Interest percentage	3.50%
3 1/2% Convertible Senior Notes | Long Term Borrowings | Convertible Note
Debt Instrument [Line Items]
Interest percentage	3.50%
7 3/4% Senior Notes | Long Term Borrowings
Debt Instrument [Line Items]
Interest percentage	7.75%
4 7/8% Senior Notes | Long Term Borrowings
Debt Instrument [Line Items]
Interest percentage	4.875%
9 5/8% Senior Notes | Long Term Borrowings
Debt Instrument [Line Items]
Interest percentage	9.625%
8 1/4% Senior Notes | Long Term Borrowings
Debt Instrument [Line Items]
Interest percentage	8.25%
9 3/4% Senior Notes | Long Term Borrowings
Debt Instrument [Line Items]
Interest percentage	9.75%