Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Computation of basic and diluted earnings per common share
Net income	$ 12,629	$ 11,937	$ 26,122	$ 22,717
Basic weighted average shares outstanding	36,128	36,762	36,531	36,635
Basic earnings per share	$ 0.35	$ 0.32	$ 0.72	$ 0.62
Effect of dilutive shares:
Stock options and restricted stock	1,312	2,329	1,536	2,376
Warrants		399		385
Diluted weighted average shares outstanding	37,440	39,490	38,067	39,396
Diluted earnings per share	$ 0.34	$ 0.30	$ 0.69	$ 0.58
Common Stock Voting [Member]
Computation of basic and diluted earnings per common share
Basic weighted average shares outstanding	36,128	34,176	35,702	34,049
Common Stock Non-Voting [Member]
Computation of basic and diluted earnings per common share
Basic weighted average shares outstanding		2,586	829	2,586

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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+ Details

- Definition

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.

+ References+ Details

- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of call options and warrants using the treasury stock method.

+ References

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-Glossary Call Option

-URI http://asc.fasb.org/extlink&oid=6506649

+ Details

- Definition

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

+ References

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+ Details

- Definition

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.

+ References+ Details

- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

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+ Details