Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Basic EPS [Abstract]
Weighted average common shares outstanding (in shares)	43,865,000	43,923,000	43,829,000	40,187,000
Net income available to common shareholders	$ 27,640	$ 16,916	$ 45,649	$ 24,565
Basic EPS (in dollars per share)	$ 0.63	$ 0.39	$ 1.04	$ 0.61
Diluted EPS [Abstract]
Weighted average common shares outstanding (in shares)	43,865,000	43,923,000	43,829,000	40,187,000
Dilutive effect of common stock options and restricted stock (in shares)	498,000	393,000	500,000	388,000
Weighted average common shares and common share equivalents (in shares)	44,363,000	44,316,000	44,329,000	40,575,000
Net income available to common shareholders	$ 27,640	$ 16,916	$ 45,649	$ 24,565
Diluted EPS (in dollars per share)	$ 0.62	$ 0.38	$ 1.03	$ 0.61
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options excluded from calculation of diluted EPS (in shares)	503,058	1,231,395	500,541	1,203,046