Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended				3 Months Ended		12 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Minimum [Member]	Jun. 30, 2013 Maximum [Member]	Jun. 30, 2013 Customer Relationships [Member]	Jun. 30, 2013 Indiana Community Bancorp [Member]	Dec. 31, 2012 Indiana Community Bancorp [Member]	Jun. 30, 2013 Branch Sales [Member]	Jun. 30, 2013 Community Banking [Member]	Jun. 30, 2012 Community Banking [Member]	Dec. 31, 2012 Community Banking [Member] Indiana Community Bancorp [Member]	Sep. 30, 2012 Community Banking [Member] Indiana Community Bancorp [Member]	Jun. 30, 2013 Other Segment [Member]	Jun. 30, 2012 Other Segment [Member]	Dec. 31, 2012 Other Segment [Member] Indiana Community Bancorp [Member]	Sep. 30, 2012 Other Segment [Member] Indiana Community Bancorp [Member]	Sep. 30, 2012 Other Segment [Member] Insurance Book Of Business [Member]
Goodwill [Line Items]
Goodwill acquired during the period			$ 562,000					$ 600,000	$ 85,600,000		$ 562,000		$ 84,600,000				$ 1,000,000
Estimated useful lives of core deposits and customer relationships					5 years	15 years
Increase in customer business relationship							100,000
Core deposit intangibles														1,300,000
Customer relationship intangibles																		1,700,000	500,000
Amortization expense of other intangible assets	$ 1,840,000	$ 1,911,000	$ 4,365,000	$ 3,932,000						$ 600,000