Consolidated Financial Statements (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Income (numerator)
Net income (loss)	$ 1,819	$ (6,932)
Shares (denominator)
Weighted-average basic common shares outstanding (in shares)	92,484	91,886
Effect of dilutive securities-stock rights (in shares)	1,740	0
Weighted-average diluted common shares outstanding (in shares)	94,224	91,886
Basic and diluted net (loss) income per share:
Basic net (loss) income per share (in dollars per share)	$ 0.02	$ (0.08)
Diluted net (loss) income per share (in dollars per share)	$ 0.02	$ (0.08)
Anti-dilutive weighted-average stock rights outstanding (in shares)	2,703	7,409

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