Earnings Per Share Reconciliation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
NUMERATOR
Net income (loss) from continuing operations	$ 22,004	$ (3,021)
Net income (loss) from discontinued operations	113	(2,087)
Less: distributed earnings allocated to nonvested restricted stock	(3)	0
Less: undistributed earnings allocated to nonvested restricted stock	(111)	0
Numerator for basic income (loss) per share	22,003	(5,108)
Plus: interest on 1.6 percent convertible senior notes due 2018	729	0
Plus: undistributed earnings allocated to nonvested restricted stock	111	0
Less: undistributed earnings reallocated to nonvested restricted stock	(95)	0
Numerator for diluted income (loss) per share	$ 22,748	$ (5,108)
DENOMINATOR
Basic earnings per share-weighted-average shares	45,434,996	44,473,870
Effect of dilutive securities:
Share-based payments (in shares)	903,321	0
1.6 percent convertible senior notes due 2018 (in shares)	7,023,780	0
Diluted earnings per share-adjusted weighted-average shares and assumed conversions	53,362,097	44,473,870
Basic
Continuing operations (in dollars per share)	$ 0.48	$ (0.07)
Discontinued operations (in dollars per share)	$ 0.00	$ (0.04)
Total (in dollars per share)	$ 0.48	$ (0.11)
Diluted
Continuing operations (in dollars per share)	$ 0.43	$ (0.07)
Discontinued operations (in dollars per share)	$ 0.00	$ (0.04)
Total (in dollars per share)	$ 0.43	$ (0.11)
1.6 percent convertible senior notes due 2018
Convertible senior notes
Interest rate stated percentage	1.60%