Loans (Schedule of Aging of Recorded Investment in Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2016		Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 2,014,003	[1],[2]	$ 1,574,027	[3],[4]
Loans Past Due	11,275	[2]	4,831	[3]
Loans Not Past Due	2,002,728	[2]	1,569,196	[3]
Accrued interest	7,913		5,952
River Valley Bancorp
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	281,252
Loans Past Due	5,248
Loans Not Past Due	276,004
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	6,275	[2]	3,159	[3]
30-59 Days Past Due | River Valley Bancorp
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	2,637
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	2,058	[2]	482	[3]
60-89 Days Past Due | River Valley Bancorp
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	1,222
90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	2,942	[2]	1,190	[3]
90 Days or More Past Due | River Valley Bancorp
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	1,389
Commercial and Industrial Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	470,381	[1]	419,176	[4]
Loans Past Due	369		323
Loans Not Past Due	470,012		418,853
Commercial and Industrial Loans and Leases | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	120		82
Commercial and Industrial Loans and Leases | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	32		117
Commercial and Industrial Loans and Leases | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	217		124
Commercial Real Estate Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	864,871	[1]	620,163	[4]
Loans Past Due	2,772		403
Loans Not Past Due	862,099		619,760
Commercial Real Estate Loans | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	1,421		136
Commercial Real Estate Loans | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	439		163
Commercial Real Estate Loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	912		104
Agricultural Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	302,954	[1]	249,699	[4]
Loans Past Due	900		0
Loans Not Past Due	302,054		249,699
Agricultural Loans | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	229		0
Agricultural Loans | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	0		0
Agricultural Loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	671		0
Home Equity Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	128,742	[1]	98,167	[4]
Loans Past Due	633		437
Loans Not Past Due	128,109		97,730
Home Equity Loans | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	387		225
Home Equity Loans | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	46		8
Home Equity Loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	200		204
Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	58,718	[1]	50,169	[4]
Loans Past Due	1,023		231
Loans Not Past Due	57,695		49,938
Consumer Loans | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	889		101
Consumer Loans | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	30		40
Consumer Loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	104		90
Residential Mortgage Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	188,337	[1]	136,653	[4]
Loans Past Due	5,578		3,437
Loans Not Past Due	182,759		133,216
Residential Mortgage Loans | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	3,229		2,615
Residential Mortgage Loans | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	1,511		154
Residential Mortgage Loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	838		668
Loans Acquired With Deteriorated Credit Quality (Included in the Total Above) | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	12,084		7,555
Loans Past Due	710		0
Loans Not Past Due	11,374		7,555
Loans Acquired With Deteriorated Credit Quality (Included in the Total Above) | 30-59 Days Past Due | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	0		0
Loans Acquired With Deteriorated Credit Quality (Included in the Total Above) | 60-89 Days Past Due | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	0		0
Loans Acquired With Deteriorated Credit Quality (Included in the Total Above) | 90 Days or More Past Due | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due	$ 710		$ 0

[1] Total recorded investment in loans includes $7,913 in accrued interest.

[2] Total recorded investment in loans includes $7,913 in accrued interest.

[3] Total recorded investment in loans includes $5,952 in accrued interest.

[4] Total recorded investment in loans includes $5,952 in accrued interest.