Fair Value Disclosures - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Available-for-sale securities:
Investment securities available-for-sale	$ 429,734	$ 425,361
Fair Value, Measurements, Recurring [Member]
Available-for-sale securities:
Investment securities available-for-sale	429,734	425,361
Total assets	431,281	426,440
Liabilities:
Total Liabilities	2,866	1,737
Fair Value, Measurements, Recurring [Member] \| U.S. government treasuries [Member]
Available-for-sale securities:
Investment securities available-for-sale	4,938	2,525
Fair Value, Measurements, Recurring [Member] \| U.S. government corporations and agencies [Member]
Available-for-sale securities:
Investment securities available-for-sale	172,142	154,264
Fair Value, Measurements, Recurring [Member] \| State and political subdivisions [Member]
Available-for-sale securities:
Investment securities available-for-sale	122,168	117,005
Fair Value, Measurements, Recurring [Member] \| Residential mortgage-backed securities [Member]
Available-for-sale securities:
Investment securities available-for-sale	90,740	78,801
Fair Value, Measurements, Recurring [Member] \| Commercial mortgage obligations [Member]
Available-for-sale securities:
Investment securities available-for-sale	27,012	61,464
Fair Value, Measurements, Recurring [Member] \| Corporate bonds [Member]
Available-for-sale securities:
Investment securities available-for-sale	5,014	4,767
Fair Value, Measurements, Recurring [Member] \| Money market mutual funds [Member]
Available-for-sale securities:
Investment securities available-for-sale	4,878	3,851
Fair Value, Measurements, Recurring [Member] \| Equity securities [Member]
Available-for-sale securities:
Investment securities available-for-sale	2,842	2,684
Fair Value, Measurements, Recurring [Member] \| Interest rate locks with customers [Member]
Available-for-sale securities:
Derivative assets	1,547	1,079
Fair Value, Measurements, Recurring [Member] \| Interest rate swap [Member]
Liabilities:
Liabilities	1,909	1,435
Fair Value, Measurements, Recurring [Member] \| Forward loan sale commitments [Member]
Liabilities:
Liabilities	54	302
Fair Value, Measurements, Recurring [Member] \| Contingent Consideration Liability [Member]
Liabilities:
Total Liabilities	903
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member]
Available-for-sale securities:
Investment securities available-for-sale	12,658	9,060
Total assets	12,658	9,060
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| U.S. government treasuries [Member]
Available-for-sale securities:
Investment securities available-for-sale	4,938	2,525
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| Money market mutual funds [Member]
Available-for-sale securities:
Investment securities available-for-sale	4,878	3,851
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| Equity securities [Member]
Available-for-sale securities:
Investment securities available-for-sale	2,842	2,684
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member]
Available-for-sale securities:
Investment securities available-for-sale	417,076	416,301
Total assets	418,623	417,380
Liabilities:
Total Liabilities	1,963	1,737
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| U.S. government corporations and agencies [Member]
Available-for-sale securities:
Investment securities available-for-sale	172,142	154,264
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| State and political subdivisions [Member]
Available-for-sale securities:
Investment securities available-for-sale	122,168	117,005
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Residential mortgage-backed securities [Member]
Available-for-sale securities:
Investment securities available-for-sale	90,740	78,801
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Commercial mortgage obligations [Member]
Available-for-sale securities:
Investment securities available-for-sale	27,012	61,464
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Corporate bonds [Member]
Available-for-sale securities:
Investment securities available-for-sale	5,014	4,767
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Interest rate locks with customers [Member]
Available-for-sale securities:
Derivative assets	1,547	1,079
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Interest rate swap [Member]
Liabilities:
Liabilities	1,909	1,435
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Forward loan sale commitments [Member]
Liabilities:
Liabilities	54	302
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member]
Liabilities:
Total Liabilities	903
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member] \| Contingent Consideration Liability [Member]
Liabilities:
Total Liabilities	$ 903

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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+ Details

- Definition

Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

+ References+ Details

- Definition

Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

+ References+ Details