Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Basic earnings per common share:
Net income available to common shareholders	$ 11,512	$ 9,063	$ 34,693	$ 24,121
Weighted-average basic common shares	21,894	14,920	18,518	14,484
Basic earnings per common share (in dollars per share)	$ 0.53	$ 0.61	$ 1.87	$ 1.67
Diluted earnings per share:
Net income available to common shareholders	$ 11,512	$ 9,063	$ 34,693	$ 24,121
Weighted-average basic common shares	21,894	14,920	18,518	14,484
Effect of dilutive securities (in shares)	234	123	199	89
Weighted-average dilutive shares	22,128	15,043	18,717	14,573
Diluted earnings per share (in dollars per share)	$ 0.52	$ 0.60	$ 1.85	$ 1.66