Employee Benefits and Retirement Plans - Summary of Changes in Stock Options (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Compensation and Retirement Disclosure [Abstract]
No. of Shares, Outstanding, Beginning balance	10,900	13,880	25,100
No. of Shares, Granted	0	0	0
No. of Shares, Expired	0	(2,980)	(11,220)
No. of Shares, Exercised	0	0	0
No. of Shares, Outstanding, Ending balance	10,900	10,900	13,880
Average Price, Outstanding, Beginning balance	$ 20.19	$ 19.08	$ 16.21
Average Price, Granted	$ 0	$ 0	$ 0
Average Price, Expired	$ 0	$ 15.00	$ 12.66
Average Price, Exercised	$ 0	$ 0	$ 0
Average Price, Outstanding, Ending balance	$ 20.19	$ 20.19	$ 19.08