Summary of Quarterly Results of Operations (Unaudited) (Details) (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
Loans:
Discount accretion PCI - cash basis	$ 108,000	$ 18,000	$ 418,000		$ 28,000
Discount accretion PCI - other	886,000	776,000	949,000		223,000	185,000	136,000
Discount accretion PNCI	1,391,000	1,286,000	1,738,000
Regular interest Purchased loans	3,439,000	3,420,000	3,651,000		978,000	872,000	835,000
All other loan interest income	19,968,000	19,429,000	20,491,000		20,758,000	20,678,000	20,751,000
Total loan interest income	25,792,000	24,929,000	27,247,000		21,987,000	21,735,000	21,722,000
Debt securities, dividends and interest bearing cash at Banks (not FTE)	2,152,000	2,235,000	2,362,000		2,485,000	2,732,000	2,712,000
Total interest and dividend income	27,944,000	27,164,000	29,609,000		24,472,000	24,467,000	24,434,000	55,108,000	48,901,000
Interest expense	2,010,000	2,128,000	2,329,000		2,465,000	2,714,000	2,730,000	4,138,000	5,444,000
Net interest income	25,934,000	25,036,000	27,280,000		22,007,000	21,753,000	21,704,000	50,970,000	43,457,000
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
Net interest income after provision for loan losses	22,563,000	21,040,000	21,851,000		16,938,000	16,192,000	14,703,000	43,603,000	30,895,000
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
Income before income taxes	8,773,000	6,390,000	10,264,000		10,788,000	4,348,000	4,382,000	15,163,000	8,730,000
Provision for income taxes	3,452,000	2,459,000	3,715,000		4,318,000	1,577,000	1,582,000	5,911,000	3,159,000
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
Per common share:
Net income (diluted)	$ 0.33	$ 0.25	$ 0.41		$ 0.40	$ 0.17	$ 0.17	$ 0.58	$ 0.35
Dividends	$ 0.09	$ 90	$ 90		$ 90	$ 90	$ 90	$ 0.18	$ 0.18