Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2011 As Restated [Member]		Jun. 30, 2011 As Restated [Member]		Jun. 30, 2012 Maximum [Member]	Jun. 30, 2011 Maximum [Member]	Jun. 30, 2011 Maximum [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount								100	100	100
Net income (loss)	$ 10,605	$ 15,304		$ 12,713	[1]	$ 60,826	[1]
Shares used in computing basic earnings per share (in shares)	42,804	42,781		42,354	[1]	42,244	[1]
Dilutive common stock equivalents (in shares)	129	130	430	386
Shares used in computing diluted earnings per share (in shares)	42,933	42,911		42,740	[1]	42,674	[1]
Basic net income (loss) per common share (price per share)	$ 0.25	$ 0.36		$ 0.30	[1]	$ 1.44	[1]
Diluted earnings per share (price per share)	$ 0.25	$ 0.36	$ 1.30	$ 0.30	[1]	$ 1.43	[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.