Business Combination (Additional Information) (Details) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
	Mar. 01, 2016 USD ($) office shares	Feb. 29, 2016 USD ($) $ / shares	Sep. 30, 2016 USD ($) office	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) office	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Number of offices | office			52		52
Assets			$ 2,979,540	$ 2,373,701	$ 2,979,540	$ 2,373,701	$ 2,373,701
Equity			340,991		340,991		252,348
Goodwill			53,671		53,671		$ 20,536
Net income included in pro forma financial information			10,297	10,348	28,865	29,391
Revenue included in pro forma financial information			32,944	$ 34,022	97,205	$ 97,758
River Valley Bancorp
Business Acquisition [Line Items]
Assets		$ 516,300
Equity		$ 56,600
Direct acquisition costs	$ 4,300
Goodwill	33,135
Intangible assets	$ 2,613
Shares of common stock issued for acquisition (in shares) | shares	1,942,000
Number of the Company's common stock for each share of RIVR converted (in shares) | shares	0.770
Cash portion, cash per share for RIVR common stock converted (in USD per share) | $ / shares		$ 9.90
Cash consideration to shareholders	$ 24,975	$ 24,975
Amount paid to persons who held options to purchase River Valley common stock	395	$ 395
Acquired receivables, fair value	309,000
Acquired receivables, unpaid principle	$ 316,400
Net income included in pro forma financial information			429		3,187
Revenue included in pro forma financial information			3,043		12,561
Non-recurring merger costs			$ 189		$ 4,318
River Valley Bancorp | Core deposits
Business Acquisition [Line Items]
Weighted average useful life					8 years
River Valley Bancorp | Southeast Indiana
Business Acquisition [Line Items]
Number of offices | office	14
River Valley Bancorp | Northern Kentucky
Business Acquisition [Line Items]
Number of offices | office	1