Securities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013 Segment	Dec. 31, 2012 Segment
Amortized cost and fair value of securities available-for-sale [Abstract]
Amortized Cost	$ 321,242	$ 326,436
Gross Unrealized Gains	2,691	3,992
Gross Unrealized Losses	(2,288)	(972)
Fair Value	321,645	329,456
Securities Available-for-Sale, Gross Unrealized Losses [Abstract]
Less Than Twelve Months	2,288	972
More Than Twelve Months	0	0
Total	2,288	972
Securities Available-for-Sale, Fair Value [Abstract]
Less than Twelve Months	174,841	119,404
More Than Twelve Months	0	0
Total	174,841	119,404
Available-for-sale securities with continuous unrealized loss position, number of securities [Abstract]
Cause	caused by increases in market interest rates.
Number of Securities	67	36
Obligations of U.S. Government agencies [Member]
Amortized cost and fair value of securities available-for-sale [Abstract]
Amortized Cost	35,377	35,787
Gross Unrealized Gains	1,113	1,314
Gross Unrealized Losses	(74)	(13)
Fair Value	36,416	37,088
Securities Available-for-Sale, Gross Unrealized Losses [Abstract]
Less Than Twelve Months	74	13
More Than Twelve Months	0	0
Total	74	13
Securities Available-for-Sale, Fair Value [Abstract]
Less than Twelve Months	4,935	5,103
More Than Twelve Months	0	0
Total	4,935	5,103
Available-for-sale securities with continuous unrealized loss position, number of securities [Abstract]
Number of Securities	1	1
Obligations of states and political subdivisions [Member]
Amortized cost and fair value of securities available-for-sale [Abstract]
Amortized Cost	48,663	43,276
Gross Unrealized Gains	413	712
Gross Unrealized Losses	(814)	(214)
Fair Value	48,262	43,774
Securities Available-for-Sale, Gross Unrealized Losses [Abstract]
Less Than Twelve Months	814	214
More Than Twelve Months	0	0
Total	814	214
Securities Available-for-Sale, Fair Value [Abstract]
Less than Twelve Months	29,063	9,535
More Than Twelve Months	0	0
Total	29,063	9,535
Available-for-sale securities with continuous unrealized loss position, number of securities [Abstract]
Number of Securities	46	24
Mortgage-backed securities [Member]
Amortized cost and fair value of securities available-for-sale [Abstract]
Amortized Cost	235,505	246,132
Gross Unrealized Gains	1,165	1,966
Gross Unrealized Losses	(1,396)	(743)
Fair Value	235,274	247,355
Securities Available-for-Sale, Gross Unrealized Losses [Abstract]
Less Than Twelve Months	1,396	743
More Than Twelve Months	0	0
Total	1,396	743
Securities Available-for-Sale, Fair Value [Abstract]
Less than Twelve Months	140,147	104,066
More Than Twelve Months	0	0
Total	140,147	104,066
Available-for-sale securities with continuous unrealized loss position, number of securities [Abstract]
Number of Securities	13	9
Money market investments [Member]
Amortized cost and fair value of securities available-for-sale [Abstract]
Amortized Cost	697	541
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	697	541
Corporate bond and other securities [Member]
Securities Available-for-Sale, Gross Unrealized Losses [Abstract]
Less Than Twelve Months	4	2
More Than Twelve Months	0	0
Total	4	2
Securities Available-for-Sale, Fair Value [Abstract]
Less than Twelve Months	696	700
More Than Twelve Months	0	0
Total	696	700
Available-for-sale securities with continuous unrealized loss position, number of securities [Abstract]
Number of Securities	7	2
Corporate Bonds [Member]
Amortized cost and fair value of securities available-for-sale [Abstract]
Amortized Cost	1,000	700
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(4)	(2)
Fair Value	996	698
Obligations of U.S. Government agencies [Member]
Amortized cost and fair value of securities held-to-maturity [Abstract]
Amortized Cost	570	570
Gross Unrealized Gains	3	4
Gross Unrealized Losses	0	0
Fair Value	$ 573	$ 574

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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