Fair Value of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Carrying amounts and fair values of financial instruments [Abstract]
Investment securities available for sale	$ 402,353	$ 299,204
Carrying Amount [Member]
Carrying amounts and fair values of financial instruments [Abstract]
Federal Reserve Bank, Federal Home Loan Bank and other stock	3,043	2,536
Carrying Amount [Member] | Level 1 [Member]
Carrying amounts and fair values of financial instruments [Abstract]
Cash and due from banks	384,656	172,559
Carrying Amount [Member] | Level 2 [Member]
Carrying amounts and fair values of financial instruments [Abstract]
Cash equivalents	1,150	0
Investment securities held to maturity	8,035	9,315
Investment securities available for sale	402,353	291,210
Loans, net of allowance	762,999	929,696
Accrued interest and loan fees receivable	4,883	6,885
Non-maturity Deposits	1,187,383	1,056,923
Time Deposits	243,731	254,949
Accrued interest payable	237	348
Carrying Amount [Member] | Level 3 [Member]
Carrying amounts and fair values of financial instruments [Abstract]
Investment securities available for sale	0	7,994
Loans Held-for-sale	907	0
Fair Value [Member]
Carrying amounts and fair values of financial instruments [Abstract]
Federal Reserve Bank, Federal Home Loan Bank and other stock
Fair Value [Member] | Level 1 [Member]
Carrying amounts and fair values of financial instruments [Abstract]
Cash and due from banks	384,656	172,559
Fair Value [Member] | Level 2 [Member]
Carrying amounts and fair values of financial instruments [Abstract]
Cash equivalents	1,150	0
Investment securities held to maturity	8,861	10,161
Investment securities available for sale	402,353	291,210
Loans, net of allowance	787,597	960,070
Accrued interest and loan fees receivable	4,883	6,885
Non-maturity Deposits	1,187,383	1,056,923
Time Deposits	245,595	257,267
Accrued interest payable	237	348
Fair Value [Member] | Level 3 [Member]
Carrying amounts and fair values of financial instruments [Abstract]
Investment securities available for sale	0	7,994
Loans Held-for-sale	$ 907	$ 0