Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Net Income
Income from continuing operations	$ 6,667	$ 7,435
Loss from discontinued operations	0	(642)
Net income	$ 6,667	$ 6,793	$ (83,353)
Basic earnings (loss) per common share
Weighted-average common shares outstanding used in earnings per share computations	62,471	62,910
Continuing operations (in dollars per share)	$ 0.11	$ 0.12
Discontinued operations (in dollars per share)	$ 0.00	$ (0.01)
Basic earnings per common share (in dollars per share)	$ 0.11	$ 0.11
Diluted earnings (loss) per common share
Shares used in diluted earnings per share computations	62,669	63,273
Continuing operations (in dollars per share)	$ 0.11	$ 0.12
Discontinued operations (in dollars per share)	$ 0.00	$ (0.01)
Diluted earnings per common share (in dollars per share)	$ 0.11	$ 0.11
Computation of Shares Used in Earnings Per Share Computations
Weighted-average common shares outstanding (in shares)	62,471	62,910
Weighted-average common equivalent shares - dilutive effect of stock options and awards	198	363
Shares used in diluted earnings per share computations	62,669	63,273