Offsetting Assets and Liabilities (Schedule of Offsetting of Liabilities) (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Repurchase agreements
Gross Amounts of Recognized Liabilities	$ 295,609,039	$ 116,080,467
Gross Amounts Offset in the Consolidated Balance Sheet
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	295,609,039	116,080,467
Gross Amounts Not Offset in the Consolidated Balance Sheet
Financial Instruments	(293,331,431)	(114,745,162)
Cash Collateral Pledged	(2,277,608)	(1,335,305)
Net Amount
Total
Gross Amounts of Recognized Liabilities	296,914,356	117,225,211
Gross Amounts Offset in the Consolidated Balance Sheet	(218,977)
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	296,695,379	117,225,211
Gross Amounts Not Offset in the Consolidated Balance Sheet
Financial Instruments	(293,331,431)	(114,745,162)
Cash Collateral Pledged	(3,363,948)	(2,480,049)
Net Amount
Interest Rate Swap [Member]
Interest rate swap agreements
Gross Amounts of Recognized Liabilities	1,305,317	1,144,744
Gross Amounts Offset in the Consolidated Balance Sheet	(218,977)
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	1,086,340	1,144,744
Gross Amounts Not Offset in the Consolidated Balance Sheet
Financial Instruments
Cash Collateral Pledged	(1,086,340)	(1,144,744)
Net Amount

The amount of the right to reclaim cash collateral under master netting arrangements that have not been offset against net derivative instrument positions.

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Fair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

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The amount as of the balance sheet date of the fair value of derivative liabilities that in accordance with the entity's accounting policy were offset against the right to reclaim cash collateral under a master netting arrangement.

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Fair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

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Fair value of the gross liabilities less the gross assets of a derivative liability or group of derivative liabilities.

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The carrying value as of the balance sheet date of securities that an institution sells and agrees to repurchase (the identical or substantially the same securities) as a seller-borrower at a specified date for a specified price, also known as a repurchase agreement, or repo. Most repos involve obligations of the federal government or its agencies, but other financial instruments, such as commercial paper, banker's acceptances, and negotiable certificates of deposit, are sometimes used in repos.

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Amount of right to receive securities collateral under master netting arrangements that have not been offset against derivative liabilities.

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Amount of derivative liabilities, securities sold under agreements to repurchase and securities loaned offset against a right to receive collateral. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities, securities sold under agreements to repurchase and securities loaned.

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Amount of right to receive securities collateral under master netting arrangements that have not been offset against derivative liabilities, securities sold under agreements to repurchase and securities loaned.

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Amount, before effects of master netting arrangements, of derivative liabilities, securities sold under agreements to repurchase and securities loaned.

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Amount of funds outstanding borrowed in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price offset against a right to receive collateral. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Amount of asset associated with funds outstanding borrowed in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price.

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Amount of right to receive cash collateral under master netting arrangements that have not been offset against securities sold under agreement to repurchase.

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Amount of right to receive securities collateral under master netting arrangements that have not been offset against securities sold under agreement to repurchase.

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Amount, before effects of master netting arrangements, of funds outstanding borrowed in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price.

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