Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Numerator for EPS:
Net income	$ 11,959	$ 9,873
Less: Preferred stock dividends	(5)	(254)
Income available to common stockholders	$ 11,954	$ 9,619
Denominator for EPS:
Weighted average common shares outstanding	39,917	39,388
Plus: Assumed conversion of stock-based compensation	793	668
Assumed conversion of preferred stock	489	488
Weighted average diluted common shares outstanding	41,199	40,544
Basic earnings per common share	$ 0.30	$ 0.24
Diluted earnings per common share	$ 0.29	$ 0.24

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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