Loans and Allowance for Loan Losses (Details 3) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	$ 14,462		$ 15,259
90 Days and Greater	6,468		8,398
Total Past Due Loans	20,930		23,657
Current Loans	3,095,166		2,960,457
Total Loans	3,116,096	3,013,498	2,984,114
Accruing Loans 90 Days or More Past Due	731	798	1,413
Non-residential real estate [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	1,561		2,269
90 Days and Greater	2,425		542
Total Past Due Loans	3,986		2,811
Current Loans	1,145,584		1,026,738
Total Loans	1,149,570		1,029,549
Accruing Loans 90 Days or More Past Due	349		1
Residential real estate [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	3,693		4,462
90 Days and Greater	1,170		1,723
Total Past Due Loans	4,863		6,185
Current Loans	732,935		689,731
Total Loans	737,798		695,916
Accruing Loans 90 Days or More Past Due	98		225
Non-consumer non-real estate [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	4,233		2,077
90 Days and Greater	135		374
Total Past Due Loans	4,368		2,451
Current Loans	729,538		690,059
Total Loans	733,906		692,510
Accruing Loans 90 Days or More Past Due	7		149
Consumer non-real estate [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	2,050		2,594
90 Days and Greater	230		354
Total Past Due Loans	2,280		2,948
Current Loans	205,463		198,684
Total Loans	207,743		201,632
Accruing Loans 90 Days or More Past Due	170		310
Other loans [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	1,706		2,749
90 Days and Greater	1,447		3,492
Total Past Due Loans	3,153		6,241
Current Loans	147,329		152,302
Total Loans	150,482		158,543
Accruing Loans 90 Days or More Past Due	43		108
Acquired loans [Member]
Age analysis of past due loans segregated by class of loans
30-89 Days Past Due	1,219		1,108
90 Days and Greater	1,061		1,913
Total Past Due Loans	2,280		3,021
Current Loans	134,317		202,943
Total Loans	136,597		205,964
Accruing Loans 90 Days or More Past Due	$ 64		$ 620