Quarterly Results of Operations (Unaudited) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Sep. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Financial Information Disclosure [Abstract]
Interest Income	$ 42,964	$ 45,347	$ 44,169	$ 43,469	$ 44,073	$ 45,085	$ 45,721	$ 46,366		$ 175,949	$ 181,245	$ 199,578
Interest Expense	4,699	5,445	6,116	7,353	7,893	9,234	9,874	10,889		23,613	37,890	56,009
NET INTEREST INCOME	38,265	39,902	38,053	36,116	36,180	35,851	35,847	35,477		152,336	143,355	143,569
Provision for loan losses	4,505	4,609	4,545	4,875	5,855	5,556	5,625	5,594		18,534	22,630	46,483
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	33,760	35,293	33,508	31,241	30,325	30,295	30,222	29,883		133,802	120,725	97,086
Noninterest Income	14,206	14,273	13,165	22,658	12,971	13,230	11,061	11,858		64,302	49,120	48,544
Noninterest Expense	34,503	34,404	34,180	34,028	33,436	34,222	34,399	33,881		137,115	135,938	142,311
INCOME BEFORE INCOME TAX	13,463	15,162	12,493	19,871	9,860	9,303	6,884	7,860		60,989	33,907	3,319
Income tax expense (benefit)	3,153	3,926	3,288	5,500	2,299	2,561	1,396	2,399		15,867	8,655	(3,590)
NET INCOME	10,310	11,236	9,205	14,371	7,561	6,742	5,488	5,461		45,122	25,252	6,909
Loss on CPP unamortized discount						(1,401)					(1,401)	(1,301)
Loss on extinguishment of trust preferred securities						(10,857)			(10,857)		(10,857)
Preferred stock dividends	(1,135)	(1,134)	(1,135)	(1,135)	(1,135)	(868)	(990)	(988)		(4,539)	(3,981)	(5,239)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS	$ 9,175	$ 10,102	$ 8,070	$ 13,236	$ 6,426	$ (6,384)	$ 4,498	$ 4,473		$ 40,583	$ 9,013	$ 11,722
Basic (usd per share)	$ 0.32	$ 0.35	$ 0.29	$ 0.46	$ 0.24	$ (0.25)	$ 0.18	$ 0.17		$ 1.42	$ 0.34	$ 0.48
Diluted (usd per share)	$ 0.32	$ 0.35	$ 0.28	$ 0.46	$ 0.24	$ (0.25)	$ 0.18	$ 0.17		$ 1.41	$ 0.34	$ 0.48
Weighted Average Number of Shares Outstanding, Basic	28,673,802	28,649,996	28,624,609	28,582,616	28,540,469	26,367,067	25,656,826	25,605,571		28,632,915	26,550,043	24,519,033
Weighted Average Number of Shares Outstanding, Diluted	28,930,392	28,888,076	28,815,019	28,754,713	28,699,505	26,367,067	25,782,799	25,763,378		28,846,684	26,693,848	24,642,425