Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Interest income
Interest on loans	$ 47,720	$ 43,813	$ 94,699	$ 86,891
Taxable interest and dividends on securities	3,506	4,415	7,035	8,942
Nontaxable interest and dividends on securities	11	23	22	52
Interest on loans held for sale	237	156	505	286
Interest on federal funds sold	21	19	55	51
Total interest and dividend income	51,495	48,426	102,316	96,222
Interest expense
Interest on deposits	2,543	2,687	5,208	5,426
Interest on borrowings	3,337	3,111	6,630	6,316
Total interest expense	5,880	5,798	11,838	11,742
Net interest income	45,615	42,628	90,478	84,480
Provision for loan losses	3,100	8,500	4,400	10,100
Net interest income after provision for loan losses	42,515	34,128	86,078	74,380
Noninterest income
Deposit account fees	4,343	3,923	8,559	7,812
Interchange and ATM fees	2,761	2,399	5,089	4,767
Investment management	4,357	3,827	8,242	7,390
Mortgage banking income	1,669	1,463	3,951	2,793
Increase in cash surrender value of life insurance policies	786	741	1,531	1,454
Loan level derivative income	816	1,371	1,348	1,699
Other noninterest income	1,960	1,259	3,694	2,978
Total noninterest income	16,692	14,983	32,414	28,893
Noninterest expenses
Salaries and employee benefits	21,594	19,775	44,309	41,211
Occupancy and equipment expenses	4,919	4,234	10,169	8,534
Advertising expense	1,479	1,473	2,652	2,210
Data processing & facilities management	1,201	1,099	2,385	2,274
FDIC assessment	934	830	1,755	1,579
Debit Card Expense	773	637	1,443	1,196
Merger and acquisition expense	754	672	2,099	672
Mortgage operations expense	715	60	1,059	102
Consulting expense	666	583	1,377	1,209
Telecommunication expense	548	666	1,203	1,284
Other noninterest expenses	8,581	6,970	16,632	14,085
Total noninterest expenses	42,164	36,999	85,083	74,356
Income before income taxes	17,043	12,112	33,409	28,917
Provision for income taxes	4,285	3,238	8,399	7,860
Net income	$ 12,758	$ 8,874	$ 25,010	$ 21,057
Basic earnings per share (in dollars per share)	$ 0.56	$ 0.41	$ 1.09	$ 0.98
Diluted earnings per share (in dollars per share)	$ 0.56	$ 0.41	$ 1.09	$ 0.97
Weighted average common shares (basic) (in shares)	22,888,155	21,623,827	22,856,132	21,592,416
Common shares equivalents (in shares)	52,144	20,377	49,104	22,251
Weighted average common shares (diluted) (in shares)	22,940,299	21,644,204	22,905,236	21,614,667
Cash dividends declared per common share (in dollars per share)	$ 0.22	$ 0.21	$ 0.44	$ 0.42