Debt (Long Term Debt Instruments) (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012 7.625% Senior Notes [Member]	Dec. 31, 2012 Capital Lease Obligations [Member]	Dec. 31, 2012 Notes Payable, Other Payables [Member]	Dec. 31, 2012 New 4.0% Notes [Member] Convertible Debt [Member]		Dec. 31, 2011 New 4.0% Notes [Member] Convertible Debt [Member]		Mar. 31, 2011 New 4.0% Notes [Member] Convertible Debt [Member]	Dec. 31, 2012 New 4.25% Notes [Member] Convertible Debt [Member]		Dec. 31, 2011 New 4.25% Notes [Member] Convertible Debt [Member]		Mar. 31, 2011 New 4.25% Notes [Member] Convertible Debt [Member]	Dec. 31, 2012 Original 4.0% Notes [Member] Convertible Debt [Member]		Dec. 31, 2011 Original 4.0% Notes [Member] Convertible Debt [Member]		Mar. 31, 2011 Original 4.0% Notes [Member] Convertible Debt [Member]	Dec. 31, 2010 Original 4.0% Notes [Member] Convertible Debt [Member]		Jun. 30, 2009 Original 4.0% Notes [Member] Convertible Debt [Member]	Dec. 31, 2012 Original 4.25% Notes [Member] Convertible Debt [Member]		Dec. 31, 2011 Original 4.25% Notes [Member] Convertible Debt [Member]		Mar. 31, 2011 Original 4.25% Notes [Member] Convertible Debt [Member]	Dec. 31, 2010 Original 4.25% Notes [Member] Convertible Debt [Member]		Nov. 30, 2009 Original 4.25% Notes [Member] Convertible Debt [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	7.625%			4.00%				4.00%	4.25%				4.25%	4.00%				4.00%				4.25%				4.25%
Principal amount				$ 105,322	[1]	$ 105,322	[1]		$ 97,000	[1]	$ 97,000	[1]		$ 9,700	[2]	$ 9,700	[2]		$ 115,000	[2]	$ 115,000	$ 3,000	[2]	$ 3,000	[2]		$ 100,000	[2]	$ 100,000
Debt instrument, weighted average interest rate		2.90%	4.00%

[1] Dilutive shares associated with the New Notes are attributable to the premium over the respective conversion prices.

[2] Dilutive shares associated with the Original Notes are attributable to the underlying principal amounts.