Components of Calculation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net loss	$ (32,611)		$ (6,718)		$ (50,148)		$ (104,976)
Weighted-average shares, basic	46,050		45,817		46,009		45,758
Effect of dilutive securities	0	[1]	0	[1]	0	[1]	0	[1]
Weighted-average shares, diluted	46,050		45,817		46,009		45,758

[1] For each of the three and nine month periods ended September 30, 2012 and 2011, an amount less than 0.1 million of potentially dilutive securities, including the Convertible Notes, stock options, restricted stock and restricted stock units, had the effect of being anti-dilutive and were excluded from the calculation of diluted earnings per common share.