Earnings Per Common Share Basic and Diluted (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator-basic and diluted
Net income (loss)	$ (50,621)	$ 22,713	$ (3,455)	$ 48,891
Denominator
Weighted average number of common shares outstanding-basic	39,094	40,387	39,212	40,446
Effect of dilutive stock options		160		590
Effect of dilutive convertible notes				224
Effect of dilutive restricted shares		555		622
Weighted average number of common shares outstanding-diluted	39,094	41,102	39,212	41,882
Earnings (loss) per common share-basic	$ (1.29)	$ 0.56	$ (0.09)	$ 1.21
Earnings (loss) per common share-diluted	$ (1.29)	$ 0.55	$ (0.09)	$ 1.17
Antidilutive stock options and restricted shares	4,586	5,421	4,677	3,678