Loans and Allowance for Loan Losses (Details 3) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	$ 14,523		$ 12,030
90 Days and Greater	7,175		7,964
Total Past Due Loans	21,698		19,994
Current Loans	3,043,741		2,841,850
Total Loans	3,065,439	3,013,498	2,861,844
Accruing Loans 90 Days or More Past Due	1,403	798	1,166
Non-residential real estate [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	2,649		1,720
90 Days and Greater	2,454		573
Total Past Due Loans	5,103		2,293
Current Loans	1,135,948		978,409
Total Loans	1,141,051		980,702
Accruing Loans 90 Days or More Past Due	285		1
Residential real estate [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	4,240		2,617
90 Days and Greater	1,288		2,208
Total Past Due Loans	5,528		4,825
Current Loans	715,621		684,344
Total Loans	721,149		689,169
Accruing Loans 90 Days or More Past Due	478		927
Non-consumer non-real estate [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	1,285		1,474
90 Days and Greater	244		324
Total Past Due Loans	1,529		1,798
Current Loans	695,887		710,640
Total Loans	697,416		712,438
Accruing Loans 90 Days or More Past Due	16		6
Consumer non-real estate [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	2,002		1,822
90 Days and Greater	183		173
Total Past Due Loans	2,185		1,995
Current Loans	198,242		196,583
Total Loans	200,427		198,578
Accruing Loans 90 Days or More Past Due	122		116
Other loans [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	1,213		3,489
90 Days and Greater	1,654		3,766
Total Past Due Loans	2,867		7,255
Current Loans	153,117		152,982
Total Loans	155,984		160,237
Accruing Loans 90 Days or More Past Due	102		89
Acquired loans [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	3,134		908
90 Days and Greater	1,352		920
Total Past Due Loans	4,486		1,828
Current Loans	144,926		118,892
Total Loans	149,412		120,720
Accruing Loans 90 Days or More Past Due	$ 400		$ 27