Stock-Based Compensation (Details) (USD $)	6 Months Ended		1 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jan. 31, 2011 Old National Bancorp [Member]	Jan. 31, 2011 Monroe Bancorp [Member]	Jun. 30, 2012 Restricted Stock Awards [Member]	Jun. 30, 2011 Restricted Stock Awards [Member]	Jun. 30, 2012 Restricted Stock Units [Member]	Jun. 30, 2011 Restricted Stock Units [Member]	Jun. 30, 2012 Stock Options [Member]	Jun. 30, 2011 Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance	3,900,000
Stock based compensation expense	$ 1,344,000	$ 1,539,000							$ 6,000	$ 41,000
Options for shares converted on acquisition				300,000
Options for shares received on acquisition			300,000
Restricted stock awards granted					54,000
Unrecognized compensation expense					1,400,000
Restricted stock expense					100,000	400,000	700,000	400,000
Reversal of expense related to performance-based restricted stock grants					$ 400,000		$ 20,000	$ 13,000
Restricted stock units granted							218,000