Net Income Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]
Net income	$ 11,447	$ 10,403	$ 10,815	$ 11,865	$ 10,310	$ 11,236	$ 9,205	$ 14,371	$ 44,530	$ 45,122	$ 25,252
Loss on CPP unamortized discount											(1,401)
Loss on extinguishment of trust preferred securities											(10,857)
Preferred stock dividends and discount accretion	(241)	(430)	(852)	(857)	(1,135)	(1,134)	(1,135)	(1,135)	(2,380)	(4,539)	(3,981)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS	11,206	9,973	9,963	11,008	9,175	10,102	8,070	13,236	42,150	40,583	9,013
Net income available to common stockholders									$ 42,150	$ 40,583	$ 9,013
Net income available to common stockholders (in shares)	32,597,145	28,806,809	28,783,407	28,716,987	28,673,802	28,649,996	28,624,609	28,582,616	29,731,420	28,632,915	26,550,043
Effect of dilutive stock options and warrants (in shares)									276,960	213,769	143,805
Net income available to common stockholders (in shares)	32,912,605	29,081,472	29,023,513	28,971,238	28,930,392	28,888,076	28,815,019	28,754,713	30,008,380	28,846,684	26,693,848
Basic net income (loss) per share:
Net income (loss) available to common stockholders (usd per share)	$ 0.34	$ 0.35	$ 0.35	$ 0.38	$ 0.32	$ 0.35	$ 0.29	$ 0.46	$ 1.42	$ 1.42	$ 0.34
Diluted net income (loss) per share:
Net income (loss) available to common stockholders (usd per share)	$ 0.34	$ 0.35	$ 0.34	$ 0.38	$ 0.32	$ 0.35	$ 0.28	$ 0.46	$ 1.41	$ 1.41	$ 0.34