Investments (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Held to Maturity
Held to maturity, amortized cost	$ 49,448,966	$ 58,489,619
Held to Maturity, Gross Unrealized Gains	2,197,000	2,933,000
Held to Maturity, Gross Unrealized Losses		1,000
Total Held to Maturity, Estimated Fair Value	51,646,000	61,422,000
Available for Sale
Available for Sale, Amortized Cost	633,155,000	621,538,000
Available for Sale, Gross Unrealized Gains	36,477,000	33,516,000
Available for Sale, Gross Unrealized Losses	833,000	1,018,000
Available for Sale, Estimated Fair Value	668,799,000	654,036,000
U.S. Treasury securities and obligations of U.S. government corporations and agencies [Member]
Held to Maturity
Held to maturity, amortized cost	1,000,000	1,000,000
Held to Maturity, Gross Unrealized Gains	33,000	54,000
Held to Maturity, Gross Unrealized Losses
Total Held to Maturity, Estimated Fair Value	1,033,000	1,054,000
Available for Sale
Available for Sale, Amortized Cost	72,105,000	59,432,000
Available for Sale, Gross Unrealized Gains	1,287,000	1,546,000
Available for Sale, Gross Unrealized Losses	174,000
Available for Sale, Estimated Fair Value	73,218,000	60,978,000
Obligations of states and political subdivisions [Member]
Held to Maturity
Held to maturity, amortized cost	47,987,000	56,966,000
Held to Maturity, Gross Unrealized Gains	2,148,000	2,857,000
Held to Maturity, Gross Unrealized Losses
Total Held to Maturity, Estimated Fair Value	50,135,000	59,823,000
Available for Sale
Available for Sale, Amortized Cost	374,212,000	372,663,000
Available for Sale, Gross Unrealized Gains	28,563,000	26,252,000
Available for Sale, Gross Unrealized Losses	252,000	39,000
Available for Sale, Estimated Fair Value	402,523,000	398,876,000
Corporate securities [Member]
Held to Maturity
Held to maturity, amortized cost	250,000	250,000
Held to Maturity, Gross Unrealized Gains	1,000	3,000
Held to Maturity, Gross Unrealized Losses
Total Held to Maturity, Estimated Fair Value	251,000	253,000
Available for Sale
Available for Sale, Amortized Cost	70,642,000	62,837,000
Available for Sale, Gross Unrealized Gains	2,665,000	1,805,000
Available for Sale, Gross Unrealized Losses	344,000	528,000
Available for Sale, Estimated Fair Value	72,963,000	64,114,000
Residential mortgage-backed securities [Member]
Held to Maturity
Held to maturity, amortized cost	212,000	274,000
Held to Maturity, Gross Unrealized Gains	15,000	19,000
Held to Maturity, Gross Unrealized Losses		1,000
Total Held to Maturity, Estimated Fair Value	227,000	292,000
Available for Sale
Available for Sale, Amortized Cost	113,352,000	119,367,000
Available for Sale, Gross Unrealized Gains	3,819,000	3,307,000
Available for Sale, Gross Unrealized Losses	27,000	44,000
Available for Sale, Estimated Fair Value	117,144,000	122,630,000
Fixed maturities [Member]
Available for Sale
Available for Sale, Amortized Cost	630,311,000	614,299,000
Available for Sale, Gross Unrealized Gains	36,334,000	32,910,000
Available for Sale, Gross Unrealized Losses	797,000	611,000
Available for Sale, Estimated Fair Value	665,848,000	646,598,000
Equity securities [Member]
Available for Sale
Available for Sale, Amortized Cost	2,844,000	7,239,000
Available for Sale, Gross Unrealized Gains	143,000	606,000
Available for Sale, Gross Unrealized Losses	36,000	407,000
Available for Sale, Estimated Fair Value	$ 2,951,000	$ 7,438,000

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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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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This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

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