Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Basic EPS [Abstract]
Weighted average common shares outstanding (in shares)	43,882,000	43,711,000	43,847,000	41,375,000
Net income available to common shareholders	$ 10,912	$ 19,257	$ 56,561	$ 43,822
Basic EPS (in dollars per share)	$ 0.25	$ 0.44	$ 1.29	$ 1.06
Diluted EPS [Abstract]
Weighted average common shares outstanding (in shares)	43,882,000	43,711,000	43,847,000	41,375,000
Dilutive effect of common stock options and restricted stock (in shares)	523,000	424,000	507,000	394,000
Weighted average common shares and common share equivalents (in shares)	44,405,000	44,135,000	44,354,000	41,769,000
Net income available to common shareholders	$ 10,912	$ 19,257	$ 56,561	$ 43,822
Diluted EPS (in dollars per share)	$ 0.25	$ 0.44	$ 1.28	$ 1.05
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options excluded from calculation of diluted EPS (in shares)	501,843	972,403	502,836	1,157,135