Earnings Per Share (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Numerator:
Net income	$ 4.5	$ 0.1	$ 15.8	$ 8.9
Less: Net income attributable to participating securities				(0.1)
Net income available to common stockholders	$ 4.5	$ 0.1	$ 15.8	$ 8.8
Denominator - Weighted-average common shares outstanding (000):
Basic	18,984	18,917	18,962	19,710
Diluted	18,984	18,917	18,962	19,710
Earnings per common share:
Basic	$ 0.24	$ 0.01	$ 0.83	$ 0.45
Diluted	$ 0.24	$ 0.01	$ 0.83	$ 0.45

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Aggregate of earnings distributed and earnings allocated to participating securities under the two-class method to the extent that participating securities may share in earnings as if all of the earnings for the period had been distributed.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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