Federal Home Loan Bank Borrowings (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Summary of contractual maturities of FHLB borrowings
Due in 2013	$ 68,529
Due in 2014	95,267
Due in 2015	99,919
Due in 2016	104,800
Due in 2017	109,918
Due in 2018 and thereafter	3,105,675
Total	$ 3,584,108	$ 3,606,411