Fair Value Measurement (Details 5) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Financial assets:
Cash and due from banks	$ 70,023	$ 81,086
Accrued interest receivable	7,201	6,636
Indemnification asset	1,807	1,997
Financial liabilities:
Accrued interest payable	975	1,036
Other borrowings	8,125	9,197
Junior subordinated debt	41,238	41,238
Carrying Amount [Member] | Level 1 inputs [Member]
Financial assets:
Cash and due from banks	70,023	81,086
Cash at Federal Reserve and other banks	732,248	667,813
Carrying Amount [Member] | Level 2 inputs [Member]
Financial assets:
Restricted equity securities	9,647	9,647
Loans held for sale	7,931	12,053
Accrued interest receivable	7,201	6,636
Financial liabilities:
Deposits	2,285,550	2,289,702
Accrued interest payable	975	1,036
Other borrowings	8,125	9,197
Junior subordinated debt	41,238	41,238
Carrying Amount [Member] | Level 3 inputs [Member]
Financial assets:
Loans, net	1,492,495	1,522,175
Indemnification asset	1,807	1,997
Fair Value [Member] | Level 1 inputs [Member]
Financial assets:
Cash and due from banks	70,023	81,086
Cash at Federal Reserve and other banks	732,248	667,813
Fair Value [Member] | Level 2 inputs [Member]
Financial assets:
Restricted equity securities	9,647	9,647
Loans held for sale	7,931	12,053
Accrued interest receivable	7,201	6,636
Financial liabilities:
Deposits	2,287,439	2,291,841
Accrued interest payable	975	1,036
Other borrowings	8,125	9,197
Junior subordinated debt	28,454	28,042
Fair Value [Member] | Level 3 inputs [Member]
Financial assets:
Loans, net	1,572,687	1,607,044
Indemnification asset	1,807	1,997
Off-balance sheet:
Commitments	5,592	5,573
Standby letters of credit	20	29
Overdraft privilege commitments	713	697
Contract Amount [Member] | Level 3 inputs [Member]
Off-balance sheet:
Commitments	559,162	557,254
Standby letters of credit	2,004	2,905
Overdraft privilege commitments	$ 71,288	$ 69,675