Borrowings (Details) (USD $)			12 Months Ended				0 Months Ended				12 Months Ended		12 Months Ended								12 Months Ended		1 Months Ended
	Dec. 31, 2012 item	Dec. 31, 2011	Dec. 31, 2012 Repurchase agreements	Dec. 31, 2011 Repurchase agreements	Dec. 31, 2012 Repurchase agreements Minimum	Dec. 31, 2012 Repurchase agreements Maximum	Jan. 30, 2013 FHLB advances	Jan. 23, 2013 FHLB advances	Jan. 16, 2013 FHLB advances	Jan. 04, 2013 FHLB advances	Dec. 31, 2012 FHLB advances	Dec. 31, 2011 FHLB advances	Dec. 31, 2012 Subordinated debt	Dec. 31, 2011 Subordinated debt	Jan. 31, 2008 Subordinated debt	Dec. 31, 2012 Notes payable and other borrowings	Dec. 31, 2011 Notes payable and other borrowings	Dec. 31, 2012 FRB	Dec. 31, 2012 Credit facility with LaSalle Bank National Association (now Bank of America) item	Jan. 31, 2008 Senior debt facility	Dec. 31, 2012 Senior debt facility LIBOR	Jan. 31, 2008 Revolving line	Nov. 30, 2009 Term debt	Dec. 31, 2012 Term debt	Dec. 31, 2011 Term debt	Jan. 31, 2008 Term debt	Dec. 31, 2012 Junior subordinated debentures	Dec. 31, 2011 Junior subordinated debentures
Borrowings
Total borrowings	$ 221,753,000	$ 104,779,000	$ 17,875,000	$ 901,000							$ 100,000,000		$ 45,000,000	$ 45,000,000		$ 500,000	$ 500,000							$ 500,000	$ 500,000		$ 58,378,000	$ 58,378,000
Maturity					1 day	90 days
Number of customers with secured balances exceeding 10% of stockholders' equity	1
Carrying amount of securities secured			26,000,000	3,700,000
Additional information related to repurchase agreements
Average daily balance during the year			4,826,000	1,957,000
Average interest rate during the year (as a percent)			0.04%	0.04%
Maximum month-end balance during the year			17,875,000	2,827,000
Weighted average interest rate at year-end (as a percent)			0.05%	0.03%
Borrowings at FHLBC as percentage of total assets											35.00%
Borrowings at FHLBC as percentage of book value of certain mortgage loans											60.00%
Bank owned FHLBC stock	6,400,000	9,300,000									6,400,000	9,300,000
Total funding availability											129,500,000	48,400,000
FHLB advances paid off								35,000,000	15,000,000	50,000,000
Advances taken on FHLBC stock							40,000,000				100,000,000
Current borrowing capacity																		41,400,000
Current secondary rate (as a percent)																		1.25%
Maximum borrowing capacity																			45,500,000	30,500,000		30,000,000				500,000
Face amount															$ 45,000,000
Variable interest rate base													three-month LIBOR								three-month LIBOR
Basis points added to reference rate (as a percent)													1.50%								0.90%
Number of financial covenants for which the entity continued to be out of compliance																			2
Increase in basis points on non compliance of covenant (as a percent)																							2.00%