Summary of Quarterly Results of Operations (Unaudited) (Details 1) (USD $)	3 Months Ended							6 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2010
Financial Summary
Net Interest Income (FTE)	$ 25,998,000					$ 21,833,000		$ 51,099,000	$ 43,620,000
Provision for loan losses	(3,371,000)	(3,996,000)	(5,429,000)		(5,069,000)	(5,561,000)	(7,001,000)	(7,367,000)	(12,562,000)
Noninterest income	10,577,000	8,265,000	10,489,000	8,029,000	14,723,000	8,251,000	9,350,000	18,842,000	17,601,000
Noninterest expense	(24,367,000)	(22,915,000)	(22,076,000)		(20,873,000)	(20,095,000)	(19,671,000)	(47,282,000)	(39,766,000)
Provision for income taxes (FTE)	(3,516,000)					(1,657,000)		(6,040,000)	(3,322,000)
Net income	5,321,000	3,931,000	6,549,000		6,470,000	2,771,000	2,800,000	9,252,000	5,571,000
Earnings per share:
Basic	$ 0.33					$ 0.17		$ 0.58	$ 0.35
Diluted	$ 0.33	$ 0.25	$ 0.41		$ 0.40	$ 0.17	$ 0.17	$ 0.58	$ 0.35
Per share:
Dividends paid	$ 0.09					$ 0.09		$ 0.18	$ 0.18
Book value at period end	$ 13.96					$ 12.82
Tangible book value at period end	$ 12.91					$ 11.82
Average common shares outstanding	15,986,000					15,922,000		15,982,000	15,891,000
Average diluted common shares outstanding	16,047,000					15,954,000		16,045,000	15,989,000
Shares outstanding at period end	15,993					15,979		15,993	15,979
At period end:
Loans, net	1,506,633,000		1,505,118,000	1,505,118,000		1,352,100,000		1,506,633,000	1,352,100,000
Total assets	2,525,618,000		2,555,597,000	2,555,597,000		2,176,184,000		2,525,618,000	2,176,184,000
Deposits	2,165,777,000		2,190,536,000	2,190,536,000		1,836,731,000		2,165,777,000	1,836,731,000
Other borrowings	60,831,000		72,541,000	72,541,000		59,234,000		60,831,000	59,234,000
Junior subordinated debt	41,238,000		41,238,000	41,238,000		41,238,000		41,238,000	41,238,000
Shareholders' equity	$ 223,229,000		$ 216,441,000	$ 216,441,000		$ 204,915,000		$ 223,229,000	$ 204,915,000	$ 200,397,000
During the period (annualized):
Return on assets	0.85%					0.51%		0.74%	0.51%
Return on equity	9.54%					5.39%		8.35%	5.44%
Net interest margin	4.46%					4.31%		4.38%	4.31%
Net loan charge-offs to average loans	0.78%					1.38%		0.97%	1.60%
Efficiency ratio	6.66%					66.80%		6.76%	65.00%
Average equity to average assets	8.89%					9.38%		8.83%	9.34%
Equity to Assets	8.84%					9.42%
Total capital to risk-adjusted assets	14.31%					14.55%