Fair Value Disclosures and Reporting, the Fair Value Option and Fair Value Measurements (Schedule of Carrying Amounts and Estimated Fair Values of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Financial Assets:
Investment securities available for sale	$ 514,466	$ 511,883
Carrying Amount [Member]
Financial Assets:
Cash and cash equivalents	47,905	50,095
Investment securities available for sale	514,466	511,883
Loans and leases, net held for investment	1,046,054	956,265
Collateral dependent impaired loans	10,852	4,791
Loans held-for-sale
Cash surrender value of life insurance policies	43,438	42,989
Other investments	7,042	7,042
Investment in limited partnership	7,029	7,276
Accrued interest receivable	5,469	5,852
Financial Liabilities:
Noninterest-bearing	400,387	390,897
Interest-bearing	990,628	975,798
Fed funds purchased and Repurchase agreements	7,985	7,251
Short-term borrowings	98,800	18,200
Long-term borrowings	2,000	6,000
Subordinated debentures	30,928	30,928
Limited partnership capital commitment	795	914
Accrued Interest Payable	116	137
Fair Value [Member]
Financial Assets:
Cash and cash equivalents	47,907	50,095
Investment securities available for sale	514,466	511,883
Loans and leases, net held for investment	1,063,099	966,599
Collateral dependent impaired loans	10,852	4,791
Loans held-for-sale
Cash surrender value of life insurance policies	43,438	42,989
Other investments	7,042	7,042
Investment in limited partnership	7,029	7,276
Accrued interest receivable	5,469	5,852
Financial Liabilities:
Noninterest-bearing	400,387	390,897
Interest-bearing	990,801	976,002
Fed funds purchased and Repurchase agreements	7,985	7,251
Short-term borrowings	98,800	18,200
Long-term borrowings	2,009	6,000
Subordinated debentures	11,501	11,428
Limited partnership capital commitment	795	914
Accrued Interest Payable	116	137
Fair Value [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets:
Cash and cash equivalents	47,907	50,095
Investment securities available for sale	2,271	2,222
Loans and leases, net held for investment
Collateral dependent impaired loans
Loans held-for-sale
Cash surrender value of life insurance policies
Other investments
Investment in limited partnership
Accrued interest receivable
Financial Liabilities:
Noninterest-bearing	400,387	390,897
Interest-bearing
Fed funds purchased and Repurchase agreements
Short-term borrowings
Long-term borrowings
Subordinated debentures
Limited partnership capital commitment
Accrued Interest Payable
Fair Value [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets:
Cash and cash equivalents
Investment securities available for sale	512,195	509,661
Loans and leases, net held for investment	1,063,099	966,599
Collateral dependent impaired loans	10,852	4,791
Loans held-for-sale
Cash surrender value of life insurance policies	43,438	42,989
Other investments	7,042	7,042
Investment in limited partnership	7,029	7,276
Accrued interest receivable	5,469	5,852
Financial Liabilities:
Noninterest-bearing
Interest-bearing	990,801	976,002
Fed funds purchased and Repurchase agreements	7,985	7,251
Short-term borrowings	98,800	18,200
Long-term borrowings	2,009	6,000
Subordinated debentures	11,501	11,428
Limited partnership capital commitment	795	914
Accrued Interest Payable	116	137
Fair Value [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets:
Cash and cash equivalents
Investment securities available for sale
Loans and leases, net held for investment
Collateral dependent impaired loans
Loans held-for-sale
Cash surrender value of life insurance policies
Other investments
Investment in limited partnership
Accrued interest receivable
Financial Liabilities:
Noninterest-bearing
Interest-bearing
Fed funds purchased and Repurchase agreements
Short-term borrowings
Long-term borrowings
Subordinated debentures
Limited partnership capital commitment
Accrued Interest Payable