Financing Activities - Other Borrowings (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
ASC 815 fair value hedge and other basis adjustments	$ (3,111)
Old National Bancorp [Member]
Debt Instrument [Line Items]
ASC 815 fair value hedge and other basis adjustments	(3,242)	(3,262)
Old National Bancorp [Member] | Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Junior subordinated debenture (variable rates of 1.84% to 1.99%) maturing March 2035 to June 2037	28,000	28,000
Old National Bank [Member]
Debt Instrument [Line Items]
Securities sold under agreements to repurchase (fixed rates 2.47% to 2.50%) maturing January 2017 to January 2018	50,000	50,000
Federal Home Loan Bank advances (fixed rates 0.21% to 8.34% and variable rates 0.32% to 0.36%) maturing April 2014 to January 2023	427,750	477,856
Capital lease obligation	4,143	4,157
ASC 815 fair value hedge and other basis adjustments	131	(363)
Total other borrowings	$ 506,782	$ 556,388