Earnings per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2011 As Restated [Member]		Sep. 30, 2011 As Restated [Member]		Sep. 30, 2012 Maximum [Member]	Sep. 30, 2011 Maximum [Member]	Sep. 30, 2011 Maximum [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount								0	0	0
Numerator:
Net income (loss)	$ 11,051	$ 26,355		$ 18,287	[1]	$ 79,113	[1]
Denominator:
Shares used in computing basic earnings per share (in shares)	42,969,000	42,852,000		42,511,000	[1]	42,334,000	[1]
Dilutive common stock equivalents (in shares)	222,000	140,000	381,000	284,000
Shares used in computing diluted earnings per share (in shares)	43,191,000	42,992,000		42,795,000	[1]	42,715,000	[1]
Basic net income (loss) per common share (price per share)	$ 0.26	$ 0.62		$ 0.43	[1]	$ 1.87	[1]
Diluted earnings per share (price per share)	$ 0.26	$ 0.61		$ 0.43	[1]	$ 1.85	[1]

[1] (1) As restated - See Note 14 “Restatement of Previously Issued Financial Statements” of Notes to Condensed Consolidated Financial Statements.See notes to Condensed Consolidated Financial Statements.