Covered Loans (Composition Of Covered Loans By Lending Classification) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011	Sep. 30, 2011
Covered Loans [Line Items]
Covered loans	$ 448,789		$ 626,360	$ 711,266
Allowance for loan losses	(4,334)		(943)	(303)
Covered loans, net	444,455
Loans Accounted For Under ASC 310-30 (Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Allowance for loan losses	(4,334)
Covered loans, net	315,239
Loans Accounted For Under ASC 310-30 (1) (Not Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Allowance for loan losses	0	[1]
Covered loans, net	129,216	[1]
Commercial [Member]
Covered Loans [Line Items]
Covered loans	69,501
Commercial [Member] | Loans Accounted For Under ASC 310-30 (Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Covered loans	36,803
Commercial [Member] | Loans Accounted For Under ASC 310-30 (1) (Not Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Covered loans	32,698	[1]
Commercial Real Estate Segment [Member]
Covered Loans [Line Items]
Covered loans	237,113
Commercial Real Estate Segment [Member] | Loans Accounted For Under ASC 310-30 (Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Covered loans	217,289
Commercial Real Estate Segment [Member] | Loans Accounted For Under ASC 310-30 (1) (Not Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Covered loans	19,824	[1]
Residential [Member]
Covered Loans [Line Items]
Covered loans	37,827
Residential [Member] | Loans Accounted For Under ASC 310-30 (Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Covered loans	37,266
Residential [Member] | Loans Accounted For Under ASC 310-30 (1) (Not Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Covered loans	561	[1]
Consumer Segment [Member]
Covered Loans [Line Items]
Covered loans	104,348
Consumer Segment [Member] | Loans Accounted For Under ASC 310-30 (Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Covered loans	28,215
Consumer Segment [Member] | Loans Accounted For Under ASC 310-30 (1) (Not Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Covered loans	76,133	[1]
Covered Loans [Member]
Covered Loans [Line Items]
Covered loans	448,789
Covered Loans [Member] | Loans Accounted For Under ASC 310-30 (Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Covered loans	319,573
Covered Loans [Member] | Loans Accounted For Under ASC 310-30 (1) (Not Purchased Credit Impaired) [Member]
Covered Loans [Line Items]
Covered loans	$ 129,216	[1]

[1] Includes loans with revolving privileges which are scoped out of FASB ASC 310-30 and certain loans which Old National elected to treat under the cost recovery method of accounting.