Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Basic EPS [Abstract]
Weighted average common shares outstanding, Basic (in shares)	36,410,000	33,063,000
Net income available to common shareholders	$ 7,649	$ 13,650
Basic EPS (in dollars per share)	$ 0.21	$ 0.41
Diluted EPS [Abstract]
Weighted average common shares outstanding, Diluted (in shares)	36,410,000	33,063,000
Dilutive effect of common stock options and restricted stock (in shares)	384,000	379,000
Weighted average common shares and common share equivalents (in shares)	36,794,000	33,442,000
Net income available to common shareholders	$ 7,649	$ 13,650
Diluted EPS (in dollars per share)	$ 0.21	$ 0.41
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options excluded from calculation of diluted EPS (in shares)	1,171,825	810,088