Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share [Abstract]
Net income as reported	$ 7,930	$ 5,832	$ 22,881	$ 18,217
Preferred stock dividend	(436)	(437)	(1,312)	(1,313)
Accretion of preferred stock discount	(212)	(195)	(621)	(575)
Net income available to common shareholders	7,282	5,200	20,948	16,329
Impact of assumed conversions
Interest on 9% convertible trust preferred securities, net of income tax	371	371	1,113	1,113
Net income available to common shareholders and assumed conversions	$ 7,653	$ 5,571	$ 22,061	$ 17,442
Weighted average common shares outstanding (in shares)	17,876,000	17,741,000	17,829,000	16,322,000
Incremental shares from assumed conversions of convertible trust preferred securities (in shares)	1,439,000	1,439,000	1,439,000	1,439,000
Additional dilutive common stock equivalents (in shares)	100,000	22,000	34,000	20,000
Weighted average diluted common shares outstanding (in shares)	19,415,000	19,202,000	19,302,000	17,781,000
Basic earnings per common share: (in dollars per share)	$ 0.41	$ 0.29	$ 1.17	$ 1.00
Diluted earnings per common share: (in dollars per share)	$ 0.39	$ 0.29	$ 1.14	$ 0.98
Antidilutive Securities Excluded from Computation of Earnings Per Share
Common stock equivalents excluded from earnings per share calculations due to anti-dilutive effect (in shares)	1,000,000	744,632	1,000,000	888,821
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share
Common stock equivalents excluded from earnings per share calculations due to anti-dilutive effect (in shares)	324,074	324,074	324,074	324,074
Convertible Debt Securities
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Convertible trust preferred securities, interest rate, stated percentage	9.00%	9.00%	9.00%	9.00%