Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Net Income (Loss)
Income (loss) from continuing operations	$ 8,309	$ (104,638)	$ 14,976	$ (97,203)
Loss from discontinued operations	0	(5,067)	0	(5,709)
Net income (loss)	$ 8,309	$ (109,705)	$ 14,976	$ (102,912)	$ (83,353)
Basic earnings (loss) per common share
Weighted-average common shares outstanding used in earnings (loss) per share computations	62,446	63,007	62,459	62,959
Continuing operations (in dollars per share)	$ 0.13	$ (1.66)	$ 0.24	$ (1.54)
Discontinued operations (in dollars per share)	$ 0.00	$ (0.08)	$ 0.00	$ (0.09)
Basic earnings (loss) per common share (in dollars per share)	$ 0.13	$ (1.74)	$ 0.24	$ (1.63)
Diluted earnings (loss) per common share
Shares used in diluted earnings (loss) per share computations	62,755	63,007	62,712	62,959
Continuing operations (in dollars per share)	$ 0.13	$ (1.66)	$ 0.24	$ (1.54)
Discontinued operations (in dollars per share)	$ 0.00	$ (0.08)	$ 0.00	$ (0.09)
Diluted earnings (loss) per common share (in dollars per share)	$ 0.13	$ (1.74)	$ 0.24	$ (1.63)
Computation of Shares Used in Earnings Per Share Computations
Weighted-average common shares outstanding (in shares)	62,446	63,007	62,459	62,959
Weighted-average common equivalent shares - dilutive effect of stock options and awards	309	0	253	0
Shares used in diluted earnings per share computations	62,755	63,007	62,712	62,959