Fair Values of Financial Instruments (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2010
Financial assets:
Cash, due from banks and federal funds sold	$ 130,029,000	$ 50,949,000	$ 105,784,000	$ 98,758,000
Interest bearing deposits with financial institutions	85,014,000	48,257,000
FHL BC and FRB stock	12,177,000	14,050,000
Bank-owned life insurance	53,416,000	52,595,000
Financial liabilities:
Noninterest bearing deposits	412,635,000	361,963,000
Junior subordinated debentures	58,378,000	58,378,000
Level 1
Financial assets:
Cash, due from banks and federal funds sold	45,015,000	2,692,000
Interest bearing deposits with financial institutions	85,014,000	48,257,000
Securities available-for-sale	53,267,000	1,524,000
Financial liabilities:
Noninterest bearing deposits	412,635,000	361,963,000
Junior subordinated debentures	16,628,000	13,172,000
Borrowing interest payable	5,447,000	4,006,000
Level 2
Financial assets:
Securities available-for-sale	336,327,000	295,928,000
Bank-owned life insurance	53,416,000	52,595,000
Loans held-for-sale	6,445,000	12,806,000
Accrued interest receivable	5,146,000	5,708,000
Financial liabilities:
Interest bearing deposits	1,360,820,000	1,382,663,000
Securities sold under repurchase agreements	13,802,000	901,000
Junior subordinated debentures	11,402,000	9,031,000
Subordinated debt	22,080,000	24,532,000
Notes payable and other borrowings	270,000	260,000
Borrowing interest payable	3,785,000	2,809,000
Deposit interest payable	1,191,000	1,718,000
Level 3
Financial assets:
Securities available-for-sale	9,301,000	10,112,000
FHL BC and FRB stock	12,177,000	14,050,000
Loans, net	1,227,552,000	1,352,335,000
Carrying Amount
Financial assets:
Cash, due from banks and federal funds sold	45,015,000	2,692,000
Interest bearing deposits with financial institutions	85,014,000	48,257,000
Securities available-for-sale	398,895,000	307,564,000
FHL BC and FRB stock	12,177,000	14,050,000
Bank-owned life insurance	53,416,000	52,595,000
Loans held-for-sale	6,445,000	12,806,000
Loans, net	1,197,848,000	1,316,988,000
Accrued interest receivable	5,146,000	5,708,000
Financial liabilities:
Noninterest bearing deposits	412,635,000	361,963,000
Interest bearing deposits	1,357,389,000	1,378,818,000
Securities sold under repurchase agreements	13,802,000	901,000
Junior subordinated debentures	58,378,000	58,378,000
Subordinated debt	45,000,000	45,000,000
Notes payable and other borrowings	500,000	500,000
Borrowing interest payable	9,232,000	6,815,000
Deposit interest payable	1,191,000	1,718,000
Fair Value
Financial assets:
Cash, due from banks and federal funds sold	45,015,000	2,692,000
Interest bearing deposits with financial institutions	85,014,000	48,257,000
Securities available-for-sale	398,895,000	307,564,000
FHL BC and FRB stock	12,177,000	14,050,000
Bank-owned life insurance	53,416,000	52,595,000
Loans held-for-sale	6,445,000	12,806,000
Loans, net	1,227,552,000	1,352,335,000
Accrued interest receivable	5,146,000	5,708,000
Financial liabilities:
Noninterest bearing deposits	412,635,000	361,963,000
Interest bearing deposits	1,360,820,000	1,382,663,000
Securities sold under repurchase agreements	13,802,000	901,000
Junior subordinated debentures	28,030,000	22,203,000
Subordinated debt	22,080,000	24,532,000
Notes payable and other borrowings	270,000	260,000
Borrowing interest payable	9,232,000	6,815,000
Deposit interest payable	$ 1,191,000	$ 1,718,000