Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balances (in shares) at Dec. 31, 2013		13,173,793
Beginning Balance at Dec. 31, 2013	$ 200,097	$ 13,174	$ 108,022	$ 84,164	$ (5,263)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	28,344			28,344
Other Comprehensive Income (Loss)	8,153				8,153
Cash Dividends ($.64, $.68, $.72 per share)	(8,450)			(8,450)
Issuance of Common Stock for:
Exercise of Stock Options (in shares)		6,640
Exercise of Stock Options	50	$ 7	43
Restricted Share Grants (in shares)		35,367
Restricted Share Grants	627	$ 35	592
Employee Stock Purchase Plan	(37)		(37)
Income Tax Benefit From Restricted Share Vesting	40		40
Ending Balances (in shares) at Dec. 31, 2014		13,215,800
Ending Balance at Dec. 31, 2014	228,824	$ 13,216	108,660	104,058	2,890
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	30,064			30,064
Other Comprehensive Income (Loss)	922				922
Cash Dividends ($.64, $.68, $.72 per share)	(9,010)			(9,010)
Issuance of Common Stock for:
Exercise of Stock Options (in shares)		12,985
Exercise of Stock Options	49	$ 13	36
Restricted Share Grants (in shares)		34,826
Restricted Share Grants	963	$ 35	928
Employee Stock Purchase Plan (in shares)		15,213
Employee Stock Purchase Plan	447	$ 15	432
Income Tax Benefit From Restricted Share Vesting	89		89
Ending Balances (in shares) at Dec. 31, 2015		13,278,824
Ending Balance at Dec. 31, 2015	252,348	$ 13,279	110,145	125,112	3,812
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	35,184			35,184
Other Comprehensive Income (Loss)	(10,216)				(10,216)
Cash Dividends ($.64, $.68, $.72 per share)	$ (10,630)			(10,630)
Issuance of Common Stock for:
Exercise of Stock Options (in shares)	7,000	4,166
Exercise of Stock Options	$ 55	$ 4	51
Acquisition of River Valley Bancorp (in shares)		1,942,429
Acquisition of River Valley Bancorp	61,919	$ 1,942	59,977
Restricted Share Grants (in shares)		36,012
Restricted Share Grants	1,407	$ 36	1,371
Income Tax Benefit From Restricted Share Vesting	200		200
Ending Balances (in shares) at Dec. 31, 2016		15,261,431
Ending Balance at Dec. 31, 2016	$ 330,267	$ 15,261	$ 171,744	$ 149,666	$ (6,404)